Commands for adding/removing additional languages

This is the current process that user must follow to add/remove additional language:

To add more languages to Code Suggestions:

Find your desired language in the list of language identifiers for VS Code. You need the Identifier for a later step.
In VS Code, open the extension settings for GitLab Workflow:
1. On the top bar, go to Code > Settings > Extensions.
2. Search for GitLab Workflow in the list, and select the gear icon.
3. Select Extension Settings.
4. In your User settings, find GitLab › Ai Assisted Code Suggestions: Additional Languages and select Add Item.
In Item, add the language identifier, and select OK.

This is quite complex, especially the part where the user has to find their language's identifier.

We have all the available information on the client, and adding/removing a language might be only a click away

Easy difficulty: Introduce a command to add/remove the current editor's language from additional languages.
Medium difficulty: The status bar item for code suggestions will support adding language to "additional languages" when user clicks it in the "language not supported" state
Medium difficulty: We set a context for each open text editor. This context will contain a boolean value based on whether the language is supported or not. Only for unsupported languages, the command for toggling supported language will be available