Add support for GPU

[haijianyang]

增加 GPU 支持

设计文档

TODO：

• 优化分配 GPU 的逻辑

测试

测试环境：2GPU 直通集群

• 并发创建 1 CP + 15Worker 集群，正常创建 2Works 挂载了指定的 GPU，其他 Workers 等待 GPU，没有出现 GPU 冲突。

[codecov]

Codecov Report

Merging #146 (deba631) into master (2a179dd) will increase coverage by 0.84%.
The diff coverage is 61.99%.

@@            Coverage Diff             @@
##           master     #146      +/-   ##
==========================================
+ Coverage   55.97%   56.82%   +0.84%     
==========================================
  Files          16       17       +1     
  Lines        2744     3157     +413     
==========================================
+ Hits         1536     1794     +258     
- Misses       1073     1207     +134     
- Partials      135      156      +21     

Files	Coverage Δ
controllers/vm_limiter.go	100.00% <100.00%> (ø)
pkg/service/collections.go	96.51% <100.00%> (+0.26%)	⬆️
pkg/service/util.go	30.32% <87.50%> (+8.62%)	⬆️
pkg/service/errors.go	0.00% <0.00%> (ø)
controllers/elfmachine_controller.go	72.87% <29.54%> (-1.93%)	⬇️
controllers/elfmachine_controller_gpu.go	82.91% <82.91%> (ø)
pkg/service/vm.go	0.00% <0.00%> (ø)

... and 1 file with indirect coverage changes