Geo - Remove RESTful support of Geo Replicable UI

Related to #219412 (closed)
Follow up for !32872 (closed)

As part of implementing SSF (via GraphQL) into the Geo frontend we have to support REST and GraphQL via the same UI components. This has caused quite a bit of conditional code that has been needed to be added. The main reason for this, is some data is still served via REST.

Data Types left to be moved from REST:

• Designs => #355660 (closed)
• API Deletion => #391189 (closed)
• Feature Flag Removal => #414381 (closed)

Proposal

1. Remove useGraphQL state variable
2. Remove computed properties that use useGraphQL
3. Remove REST based paginationData
4. Remove REST based GlPagination
5. Remove REST api methods
6. Remove REST vuex actions
7. Remove REST vuex mutations