https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24034 introduced
a regression where only the first 20 branches were used to determine
whether a branch has been merged because the pagination was applied
incorrectly. Requesting the second page of branches via the API would
always have the wrong merge status. We fix this by properly paginating
the branches before requesting their merge status.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/56250

Prepares suggestion implementation for multi-line support

See merge request gitlab-org/gitlab-ce!26057

Adds the groundwork needed in order to persist multi-line suggestions,
while providing the parsing strategy which will be reused for the
**Preview** as well.

Allow multiple repositories per project

See merge request gitlab-org/gitlab-ce!26539

Backport EE API parameters in lib/api

See merge request gitlab-org/gitlab-ce!26369

This backports the EE specific parameters for API::Parameters, wrapping
them in a conditional.

This backports the EE specific parameters for API::Users, and wraps them
in a conditional.

This backports the API parameters from API::Settings that were added in
EE, wrapping them in a conditional.

This backports EE specific parameters EE adds to API::ProtectedBranches,
and wraps them in a conditional.