feat: session status-history handler

[jopemachine]

Follow-up PR to #480.
Ref: #412.

Currently, session status-history raises 404 error because the status-history handler does not exist.

$ ./backend.ai session status-history mysession
✘ BackendAPIError: 404 Not Found
  Unknown URL path.
  ➜ Data: '/session/mysession/status-history'

Result

In this PR, session status-history command prints the status-history like below.

$ ./backend.ai session status-history mysession
∙ status_history: OrderedDict([('PENDING', '2023-02-27T00:48:12.723794+00:00'), ('RUNNING', '2023-02-27T00:48:18.579231+00:00'), ('PREPARING', '2023-02-27T00:48:13.530317+00:00'), ('SCHEDULED', '2023-02-27T00:48:13.498186+00:00')])
✓ Actual Resource Allocation Time: {'result': {'seconds': 0, 'microseconds': 0}}

But I think it would be nice to find better formatting for the status-history instead of just printing OrderedDict.

[achimnol]

Please refer ai.backend.client.output and its usage for handling console/json outputs of the client SDK in a single abstraction.

[CLAassistant]

All committers have signed the CLA.

[jopemachine]

Please refer ai.backend.client.output and its usage for handling console/json outputs of the client SDK in a single abstraction.

I updated this PR, but I think there might be some missing session types in https://github.com/lablup/backend.ai/pull/1116/files#diff-617867996601b356e12de71696162ef8390144f3ba6aaba12da78cb7efabf4f7R961-R969.

[achimnol]

Let's improve the console output:

• Order the status changes in the state machine order (e.g., PENDING, SCHEDULED, PULLING, PREPARING, RUNNING).
  • I think we could generalize the status history loop.
• Display relative duration between each status change.
• Format all relative timedelta values using human readable formats.

[achimnol]

We will revisit this PR after converting the status history columns from mappings to lists in the chronological order.

[jopemachine]

This will be resolved in #3201.