[DOC] Update documentation for remote segment upload backpressure settings and also add this to cluster settings

[ashking94]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request and all versions that are affected.
We have toned down on the number of remote backpressure settings. We have removed the below settings -

• remote_store.segment.pressure.upload_bytes_moving_average_window_size
• remote_store.segment.pressure.upload_time_moving_average_window_size
• remote_store.segment.pressure.upload_bytes_per_sec_moving_average_window_size

Apart from this we have introduced another cluster setting - remote_store.moving_average_window_size which is used to replace all the above settings that have been removed.

Remote segment backpressure web page - https://opensearch.org/docs/latest/tuning-your-cluster/availability-and-recovery/remote-store/remote-segment-backpressure/
Cluster setting webpage - https://opensearch.org/docs/latest/api-reference/cluster-api/cluster-settings/

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.