This commit updates the Releases page to make its initial GraphQL
query earlier in the application lifecycle, allowing the content to
load more quickly.

Changelog: performance

This commit updates the directory structure of release-related GraphQL
queries/mutations/fragments.

Add releases_sort component
Fetch over REST and GraphQL

This commit adds a new GraphQL that fetches a single release.

This commit updates the Releases page to include pagination when in
"GraphQL mode".

Because this is the last step in the GraphQL feature, this MR also
enables the `graphql_releases_page` feature flag by default.

This commit update the Releases page to fetch its data from GraphQL
instead of from the REST endpoint. This change is hidden behind the
graphql_releases_page feature flag.