Delete release checklist template

The release checklist is inside of another project:
https://gitlab.com/gitlab-org/ci-cd/runner-release-helper. Which is the
single source of truth for releases.
5 jobs for docs/add-process-file in 5 minutes and 5 seconds (queued for 9 seconds)
Status Job ID Name Coverage
  Prebuild
passed #246959927
check feature flags docs

00:01:09

manual #246959924
allowed to fail manual
review-docs-deploy
 
  Test
passed #246959931
docs lint

00:01:23

passed #246959929
allowed to fail
license_management

00:03:55

 
  Cleanup
manual #246959933
allowed to fail manual
review-docs-cleanup