XDCR - Synchronize current replication settings with official documentations

The documentation page https://docs.couchbase.com/server/current/rest-api/rest-xdcr-adv-settings.html#xdcr-advanced-settings-rest is missing a good number of replication settings.

XDCR team internally is responsible to add new replication settings, but have not done the due diligence to update the documentation page.

We should go through the current code base and add the missing replication settings, their expected formats, and help texts, such that users can benefit.