MVP of container code editor

Deprecated, we'l try the sync for an editor: https://gitlab.com/gitlab-org/gitlab-ce/issues/22876

Old:

1. We use CodeMirror as the editor. (Thimble relies on Bramble. Bramble is Brackets. Brackets is CodeMirror.)
2. We connect it to the container in the same way as the openshift editor #22843 (closed) if that is practical
3. We link to the code editor from the environment next to the url to access the app and the url for the console

/cc @jschatz1