### What changes were proposed in this pull request?
Make appUniqueId a member of ShuffleClientImpl and remove applicationId from RPC messages across client side, so it won't cause compatibility issues.
### Why are the changes needed?
Currently Celeborn Client is bound to a single application id, so there's no need to pass applicationId around in many RPC messages in client side.
### Does this PR introduce _any_ user-facing change?
In some logs the application id will not be printed, which should not be a problem.
### How was this patch tested?
UTs.
Closes#1621 from waitinfuture/appid.
Authored-by: zky.zhoukeyong <zky.zhoukeyong@alibaba-inc.com>
Signed-off-by: zky.zhoukeyong <zky.zhoukeyong@alibaba-inc.com>
6b82ecdfa0