JetBrains sign in via license key

[brikelly]

This task is to create an equivalent of this PR for VS Code.

The desired UX is as follows:

• Users who cannot use GitHub or GitLab to sign in can instead enter a license key. This key will be retrieved through other means, e.g. by contacting our support team.
• After installing the AppMap plugin from the marketplace, a new menu option will be available under Tools -> AppMap called Enter license key. This can be placed at the bottom, in the third section of items:
  
• Once the user clicks on this menu item, they are presented with a modal dialog box with title "Enter your AppMap license key" and with a single text entry box named "license key". If they click the "OK" button then the auth checks occur.
• The auth checks may require opening a browser similar to how the existing sign in is done.
• If the key verification completes successfully, the "Sign In" panel should disappear and be replaced with the normal AppMap functionality, just as the existing GitHub/Lab flow does. A notification should also be displayed saying "Logged into AppMap".
• If the key verification fails, a notification should be displayed saying "License key verification failed".

Notes:

• If the user is already logged in with GitHub/Lab, entering a license key will replace their login with the new license key login instead. There is no need to warn the user that they're already logged in with another method.

[appland-release]

🎉 This issue has been resolved in version 0.54.0 🎉

The release is available on:

• v0.54.0
• GitHub release

Your semantic-release bot 📦🚀