Inject the glab CLI into every workspace

Problem to solve

The glab CLI offers valuable features for interacting with GitLab, but it requires a developer to be aware of its existence and take active steps to install it. Remote development workspaces are ephemeral environments meant to improve the overall developer experience by eliminating the need to configure and maintain a local development environment. It would be ideal if glab was available in every workspace to provide additional tools to help reduce friction.

Proposal

Inject the CLI into a workspace much like we do the editor. It should be installed by default for every workspace and authenticated with the user's PAT.

Open questions/concerns/blockers

1. Is there any scenario where a customer would not want to run the CLI other than "personal preference"? Any privacy or security concerns with making this a required installation?
2. Handling authentication is the big barrier before we can start this. glab requires a PAT but supports environment variables. After we figure out how we are going to pass credentials into the workspace, we may be able to re-use the same approach for glab.