Proof of concept: attach Web IDE to CI job with web terminal to run tests

We want to make it possible to run tests against the code in the Web IDE live. To do this we will use a CI runner, launch a new kind of web IDE job (similar to a ChatOps job) and attach to the job, and make a web terminal available in the Web IDE.

Proposal

Although this is a proof of concept, ideally we should be able to merge it behind a feature switch.

• Add a 'Web Terminal' tab to the right panel
  • Add a 'Start' button to launch web-ide job with using a runner with the web-ide tag
  • Add a web terminal interface that will be interactive once the job is launched
• Make sure web-ide job does eventually timeout (should be 30 mins)
• Make sure we don't create loads of useless CI pipelines

Not in scope:

• Stopping the runner (just let it time out)
  • when I leave the page
  • manually
• Syncing files to/from the runner

Links

• https://gitlab.com/gitlab-org/gitlab-ee/issues/5274
• https://gitlab.com/gitlab-org/gitlab-ce/issues/25990

Design

• Button to start the runner
• Notice of timeout
• The terminal should auto scroll btw, if the user decides to scroll it stops until the user scrolls to the bottom again (after which it should auto enable again)
• Line wrapping should be enabled