Update parallel RL

[lihuoran]

Description

Update parallel RL. Now, MARO RL has full ability to run rollout & training under parallel mode.

• Refine EnvSampler
  • Do not explicitly pass info_list. Instead, store info_list in the EnvSampler.
  • Add merge_metrics() to support metrics aggregation in parallel rollout.
  • Add EnvSamplerInterface as the base interface for EnvSampler and BatchEnvSampler.
  • Complete other previously missing features.
• Trainer
  • Complete functions for parallel training (@remote functions).
• MISCs
  • Add parallel RL configs for GYM tasks.
  • Fix several minor bugs.

Linked issue(s)/Pull request(s)

• issue_number

Type of Change

• [ ] Non-breaking bug fix
• [ ] Breaking bug fix
• [ ] New feature
• [ ] Test
• [ ] Doc update
• [ ] Docker update

Related Component

• [ ] Simulation toolkit
• [ ] RL toolkit
• [ ] Distributed toolkit

Has Been Tested

• OS:
  • [ ] Windows
  • [ ] Mac OS
  • [ ] Linux
• Python version:
  • [ ] 3.7
  • [ ] 3.8
  • [ ] 3.9
• Key information snapshot(s):

Needs Follow Up Actions

• [ ] New release package
• [ ] New docker image

Checklist

• [ ] Add/update the related comments
• [ ] Add/update the related tests
• [ ] Add/update the related documentations
• [ ] Update the dependent downstream modules usage