Update and rename MAINTAINERS.md to MAINTAINERS_COMMITTER.md

[RongGu]

add committer list.

Ⅰ. Describe what this PR does

Ⅱ. Does this pull request fix one issue?

Ⅲ. List the added test cases (unit test/integration test) if any, please explain if no tests are needed.

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov]

Codecov Report

Merging #1514 (bbd62c7) into master (4d729ac) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1514   +/-   ##
=======================================
  Coverage   70.69%   70.69%           
=======================================
  Files         235      235           
  Lines       12909    12909           
=======================================
  Hits         9126     9126           
  Misses       2805     2805           
  Partials      978      978           

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[cheyang]

@RongGu Could you please fix the DCO issue by following the guide:

https://github.com/fluid-cloudnative/fluid/pull/1514/checks?check_run_id=5511329692

1. Ensure you have a local copy of your branch by [checking out the pull request locally via command line](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/checking-out-pull-requests-locally).
2. In your local branch, run: git rebase HEAD~2 --signoff
3. Force push your changes to overwrite the branch: git push --force-with-lease origin RongGu-patch-8

Thanks.

[RongGu]

@RongGu Could you please fix the DCO issue by following the guide:

https://github.com/fluid-cloudnative/fluid/pull/1514/checks?check_run_id=5511329692

1. Ensure you have a local copy of your branch by [checking out the pull request locally via command line](https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/checking-out-pull-requests-locally).
2. In your local branch, run: git rebase HEAD~2 --signoff
3. Force push your changes to overwrite the branch: git push --force-with-lease origin RongGu-patch-8

Thanks.

Thank you. This PR is resbumitted here #1517.