Disable extension marketplace in VSCode Web IDE

Problem to solve

The extension marketplace in VS Code provides a powerful way to extend the IDE and customize the experience. However, the extensions themselves are written and distributed by third parties, each with its own license and privacy policies.

Proposal

• Disable the extensions panel until we can implement a user flow that allows developers to make an informed decision about whether to install extensions
• Provide an affordance in the UI that links to &7685 which is our iteration plan for enabling extensions

Next iterations

We'll enable extensions following this rough plan:

1. Initial state - no extensions allowed
2. Pre-install the GitLab Workflow extension
3. Extensions enabled after confirming EULA or similar
4. Instance-level control over whether to allow extensions
5. Extension allow list functionality