[Remote Store] Integration of remote translog and remote segment store

[sachinpkale]

Describe the solution you'd like

• Once remote segment store and remote translog are implemented, the next step is to make sure that both of these stores are in sync.
• Today, translog and segment store on local work together in order to provide consistent experience of the indexed data. This involves purging the translog only after commit is successful and all the segment files are fsynced to the disk
• For an OpenSearch cluster with remote store enabled, we have:
  • Remote Translog
  • Local Segment Store
  • Remote Segment Store
• In this issue, we will discuss different approaches to keep all the three stores mentioned above in sync.