[Refactor] refactor migration scheduler

[KuilongCui]

The current migration logic is somewhat confusing, as the filter contains the logic for sorting instances by load. In the refactored logic, we aim to adhere to the Single Responsibility Principle as much as possible:

1. The MigrationFilter will only handle filtering-related logic, with specific filter strategies determined by pair_migration_type.
2. The PairMigrationPolicy will process the source and destination instance information after filtering.

[github-actions]

prefill	p25	p50	p75	p95	p99	mean
latency(ms)	33707.14	106413.80	200891.57	243231.90	246857.76	116510.99

decode	p25	p50	p75	p95	p99	mean
latency(ms)	52.74	58.43	68.37	116.33	215.33	66.80

[github-actions]

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	312.00 MB	320.00 MB	472.00 MB	536.00 MB	544.00 MB	560.00 MB	728.00 MB
rpc_speed(GB/s)	1.03	1.52	1.79	1.91	2.03	2.08	2.17	2.13	2.17	2.23	2.30	2.38	2.41	2.45	2.29	2.43	2.54	2.58	2.44	2.47	2.46	2.43	2.54	2.58	2.68	2.80	3.13	2.96	2.96	3.19	3.07

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	312.00 MB	472.00 MB	536.00 MB	560.00 MB	688.00 MB	736.00 MB	960.00 MB
gloo_speed(GB/s)	1.02	1.67	2.08	2.42	2.68	2.74	2.79	2.84	2.85	3.06	3.44	3.52	3.60	3.41	3.14	2.75	2.54	3.06	1.77	2.27	3.09	2.84	2.98	3.58	2.78	2.76	3.09	2.85	2.94	3.04	2.96

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	312.00 MB	336.00 MB	376.00 MB	480.00 MB	488.00 MB	544.00 MB	552.00 MB	560.00 MB	568.00 MB	688.00 MB	728.00 MB	960.00 MB
nccl_speed(GB/s)	0.19	0.40	0.60	0.73	0.93	1.08	1.21	1.32	1.63	1.83	2.09	2.45	2.33	2.45	2.27	2.34	2.73	3.13	3.59	3.82	3.23	3.68	3.38	3.69	4.79	5.26	5.94	5.84	4.48	4.19	4.06	4.37	5.50	6.85	5.74

[s5u13b]

LGTM. May be we should add the auto-scaling e2e test in the future.

[github-actions]

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	200.00 MB	208.00 MB	232.00 MB	280.00 MB	312.00 MB	472.00 MB	480.00 MB	544.00 MB	552.00 MB	960.00 MB
rpc_speed(GB/s)	1.09	1.63	1.86	2.03	2.11	2.22	2.31	2.30	2.42	2.42	2.52	2.51	2.59	2.55	2.62	2.66	2.58	2.70	2.68	2.67	2.68	2.60	2.75	2.73	2.69	2.76	2.94	2.81	2.98	3.18	3.23	3.33	3.36	3.69

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	200.00 MB	216.00 MB	288.00 MB	312.00 MB	320.00 MB	336.00 MB	344.00 MB	480.00 MB	560.00 MB	568.00 MB
gloo_speed(GB/s)	1.01	1.68	2.10	2.45	2.48	2.69	2.88	2.79	3.19	3.09	2.96	3.60	3.67	3.97	3.30	3.00	2.58	1.88	2.73	2.57	1.50	3.15	2.83	2.92	2.85	3.68	3.40	3.39	3.39	4.18	3.77	3.04	2.91	3.17

[s5u13b]

reviewing

[github-actions]

prefill	p25	p50	p75	p95	p99	mean
latency(ms)	22153.28	65582.49	108632.85	148149.97	151150.15	66590.02

decode	p25	p50	p75	p95	p99	mean
latency(ms)	52.78	55.48	62.65	103.08	198.50	61.47

[s5u13b]

This pr seems a bit over-design for me. I don't quite understand the necessity here.

[github-actions]

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	200.00 MB	216.00 MB	224.00 MB	320.00 MB	344.00 MB	368.00 MB	472.00 MB	536.00 MB	696.00 MB	960.00 MB
rpc_speed(GB/s)	1.10	1.65	1.93	2.10	2.08	2.30	2.36	2.41	2.45	2.45	2.50	2.51	2.58	2.61	2.63	2.65	2.63	2.57	2.48	2.64	2.52	2.68	2.72	2.73	2.74	2.97	2.65	2.44	2.95	3.03	3.18	3.39	3.42	3.78

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	224.00 MB	232.00 MB	312.00 MB	336.00 MB	344.00 MB	352.00 MB	560.00 MB	696.00 MB
gloo_speed(GB/s)	1.05	1.64	2.11	2.41	2.58	2.73	3.03	2.99	3.11	3.43	3.03	3.52	2.81	3.17	3.32	2.97	2.77	3.10	2.92	3.04	2.88	3.00	3.06	2.94	4.07	0.77	3.09	3.48	4.02	4.04	3.15	2.87

[github-actions]

prefill	p25	p50	p75	p95	p99	mean
latency(ms)	14193.58	59013.98	129412.58	150639.29	152151.83	66652.76

decode	p25	p50	p75	p95	p99	mean
latency(ms)	53.20	56.93	65.99	99.86	147.35	62.15

[github-actions]

prefill	p25	p50	p75	p95	p99	mean
latency(ms)	7655.60	53606.06	117234.86	147139.14	168672.04	62216.60

decode	p25	p50	p75	p95	p99	mean
latency(ms)	52.08	55.82	64.49	109.39	238.70	63.93

[github-actions]

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	176.00 MB	200.00 MB	208.00 MB	248.00 MB	304.00 MB	352.00 MB
rpc_speed(GB/s)	1.11	1.61	1.88	2.06	2.13	2.20	2.30	2.31	2.41	2.42	2.44	2.52	2.59	2.58	2.57	2.64	2.64	2.69	2.81	2.87	2.69	2.86	2.26	2.53	3.10	3.32

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	184.00 MB	192.00 MB	312.00 MB
gloo_speed(GB/s)	0.99	1.67	2.00	2.38	2.54	2.67	2.83	3.10	3.07	3.10	2.85	3.21	3.47	2.98	3.56	2.31	2.87	2.68	3.02	2.93	1.60	2.40	2.29	2.95	1.78

[github-actions]

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	168.00 MB	184.00 MB	192.00 MB	200.00 MB	208.00 MB	280.00 MB	560.00 MB
rpc_speed(GB/s)	1.06	1.55	1.82	1.96	2.10	2.18	2.18	2.24	2.29	2.42	2.46	2.51	2.50	2.57	2.62	2.57	2.58	2.58	2.67	2.63	2.93	2.74	2.65	2.68	2.88	3.30

migration_size	8.00 MB	16.00 MB	24.00 MB	32.00 MB	40.00 MB	48.00 MB	56.00 MB	64.00 MB	72.00 MB	80.00 MB	88.00 MB	96.00 MB	104.00 MB	112.00 MB	120.00 MB	128.00 MB	136.00 MB	144.00 MB	152.00 MB	160.00 MB	168.00 MB	176.00 MB	192.00 MB	200.00 MB	208.00 MB	216.00 MB
gloo_speed(GB/s)	1.02	1.70	2.03	2.47	2.52	2.74	2.83	3.11	3.11	3.49	2.99	3.33	3.22	3.31	3.31	2.37	2.24	2.84	3.20	2.79	2.94	2.86	2.26	3.36	3.50	3.88

[github-actions]

prefill	p25	p50	p75	p95	p99	mean
latency(ms)	23088.66	47944.24	110676.57	142799.81	156045.68	62858.89

decode	p25	p50	p75	p95	p99	mean
latency(ms)	52.27	57.75	71.68	125.52	254.69	67.58