remove unused pages (routes and components)

Created by: sqs

See commit messages for a full list of the pages removed. All of these routes and components have been unused for a long time and were just cluttering up our code.

None of these removals are changelog-worthy because they are either (1) removing a redirect that was documented in the changelog originally and has long since stopped being useful or (2) about a feature that was never released and nobody is using.