[DTensor & DModule & DOptim] feature updates

[jc-bytedance]

In this PR, we update some features in our DTensor & DModule & DOptim implementations, Yo~

DTensor Updates:

1. Support more dtensor ops.
2. Sharding Strategy Updates.

DModule Updates:

1. Decouple uneven support and run check.
2. Reduce some CPU overhead.

DOptim Updates:

1. More fridenly API.
2. Unit test updates.
3. Reorder some communication for better results.

Other Updates/fixes:

1. Some minor update on our nano GPT model and test results.