### What changes were proposed in this pull request?
In [CELEBORN-1535](https://issues.apache.org/jira/browse/CELEBORN-1535), we support to disable master workerUnavilableInfo expiration.
In this PR, a new RestAPI introduced for manually remove unavailable workers. Then it can be used on demand.
### Why are the changes needed?
To cleanup the works unavailable info on demand manually if we disable the expiration.
### Does this PR introduce _any_ user-facing change?
Yes, a new RESTful API.
### How was this patch tested?
UT.
Closes#2658 from turboFei/support_cleanup.
Authored-by: Wang, Fei <fwang12@ebay.com>
Signed-off-by: Shuang <lvshuang.xjs@alibaba-inc.com>
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