Issue #3484714: Increase route build speed

Fixes #3484714. Route building recomputed JSON:API resource type names for every view instead of reusing them across views that share an entity type. During database updates, when the cache backend can't persist writes, this took over 45 minutes on one reported site.

Caches resource type names per entity type during route building, and adds test coverage for views sharing an entity type. Measured at the reported scale (46 views, 13 content types): 637 calls to ResourceTypeRepository::get() before, 13 after.

Tests green on D10 and D11.