[Improvement] Seprate code for the different roles in spark rssShuffleManager

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://www.apache.org/foundation/policies/conduct)

### Search before asking

- [X] I have searched in the [issues](https://github.com/apache/incubator-uniffle/issues?q=is%3Aissue) and found no similar issues.

### What would you like to be improved?

For the current codebase, the different roles codes are all in the same `RssShuffleManager` , this is hard to read and understand for the new bies.

### How should we improve?

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

Start by reading the current RssShuffleManager implementation and identify the different roles whose code is combined there. Trace how those roles are used before deciding how to separate them. Done means the roles are separated into clearer code while preserving the existing shuffle-manager behavior; the issue does not name specific tests to run.

Written by the indexing model from the issue text.