Get version information from API call

Description

Some integrations benefit from getting version information from GitLab. Both CE/EE and version number.

Proposal

Add an API call, for any authenticated user

/version

that returns GitLab version information. For instance:

{
  "version" : "8.12.1-ee"
}

Links / references

Related issue: https://gitlab.com/gitlab-org/gitlab-ee/issues/993

Closing in favour of the original issue

Status changed to closed