Add API support for pipeline schedule

Closes #30892

See merge request !11307

Allow PostReceivePack to be enabled with Gitaly

Closes gitaly#246

See merge request !11809

Return nil when looking up config for unknown LDAP provider

Closes #29342

See merge request !11804

Revert "Merge branch 'grpc-1.3.4' into 'master'"

See merge request !11813

This reverts merge request !11645

Resolve "Allow to disable username on checkout url"

Closes #30410 and #30174

See merge request !11792

Remove extra bottom padding on Job log page

Closes #30502

See merge request !11791

Enable Gitaly by default in GitLab 9.3

Closes gitaly#242

See merge request !11796

Avoid crash when trying to parse string with invalid UTF-8 sequence

See merge request !11770

Don’t create comment on JIRA if link already exists

Closes #25373

See merge request !11485