[Improvement] Possible concurrency issues for KvGrabageCollector

[yuqi1129]

What would you like to be improved?

Currently, we would use the following steps to write kv data within a transaction.

Main thread:

1. Write a real key/value pair into the storage.
2. Write a commit mark to indicate that the pair is committed.

KvGarbageCollector will periodically scan the storage. If it finds a key/value pair that without a corresponding commit mark for it, KvGarbageCollector will review it as data that is uncommitted, then KvGarbageCollector will clean the data.

There is a chance that the "KvGarbageCollector" thread operates between steps 1 and 2. Fore more, please see the code. https://github.com/datastrato/gravitino/blob/99f2ede127c6977c0cf7c2a137166a8ca780c369/core/src/main/java/com/datastrato/gravitino/storage/kv/KvGarbageCollector.java#L91-L117

How should we improve?

As the time of the writing process in RocksDB is relatively fast, we can make KvGarbageCollector only remove uncommitted data that was written into storage 10 minutes ago, then things will be solved.