replace dm-tree with treevalue

[wangsiping97]

Description

Replaced dm-tree with treevalue for better performance.

Motivation and Context

treevalue is significantly faster than dm-tree.

After fix, envpool's speedup increased from ~0.5x to ~0.7x:

Namespace(domain='cheetah', seed=0, task='run', total_step=200000)
100%|███████████████████████████████████████████████████████████████████████████████████████████████| 200000/200000 [00:16<00:00, 11769.05it/s]
FPS(dmc) = 11766.68
100%|████████████████████████████████████████████████████████████████████████████████████████████████| 200000/200000 [00:24<00:00, 8241.72it/s]
FPS(envpool) = 8241.51
EnvPool Speedup: 0.70x

• I have raised an issue to propose this change (required for new features and bug fixes)

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds core functionality)
• New environment (non-breaking change which adds 3rd-party environment)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (update in the documentation)
• Example (update in the folder of example)

Implemented Tasks

• replace dm-tree with treevalue in envpool

Checklist

• I have read the CONTRIBUTION guide (required)
• My change requires a change to the documentation.
• I have updated the tests accordingly (required for a bug fix or a new feature).
• I have updated the documentation accordingly.
• I have reformatted the code using make format (required)
• I have checked the code using make lint (required)
• I have ensured make bazel-test pass. (required)