Add GitLab comment banner to the head of our frontend assets

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

Using webpack.BannerPlugin (documentation) we can inject a banner to the head of our frontend assets.

This could contain some basic copyright info, and maybe list the current tag and git SHA to help with debugging.

/**
 * GitLab Community Edition v9.2-pre (8caf29ea)
 * © 2017 GitLab Inc.
 * MIT License (https://gitlab.com/gitlab-org/gitlab-ce/blob/master/LICENSE)
 */

or

/**
 * GitLab Enterprise Edition v9.1.4 (8caf29ea)
 * © 2017 GitLab Inc.
 */

Possible complications:

  1. we'd need to pull in the tag and SHA values dynamically at build time, so perhaps this would only be done in the omnibus build process via a special environment variable

  2. we'd want to make sure this doesn't change the digest value of long-term cache bundles like our commons bundle. this might have the odd effect of a user's browser keeping a version that reports a different version tag in the comment banner than the actual version of gitlab, but it's better to have this than to break the cache digest on every build.

Edited by 🤖 GitLab Bot 🤖