Reduced the memory usage, db queries and cache hits loading revisions

Reduced the memory usage, db queries and cache hits loading revisions

Updated revision listing to only fetch required fields, massively
reducing memory usage by not loading content.
This also updates user avatar handling to effectively cache the avatar
url within request to avoid re-searching from cache, which may improve
performance of others areas of the application.
This also upates handling of the revisions list view to extract table
row to its own view to break things down a bit.

For #3633