Switch To Using ExtensionContext.globalState to Store Information Rather Than On User's Filesystem

[chrstinalin]

I was curious when (if ever) the workspace arg would be undefined, so I started poking through some VSCode docs. While trying to look up information about vscode.ExtensionContext I found some docs that state (emphasis mine):

ExtensionContext.globalState: A global storage where you can write key/value pairs. VS Code manages the storage and will restore it for each extension activation. You can selectively synchronize key/value pairs in global storage by setting the keys for sync using setKeysForSync method on globalState.

On the surface this seems like it would be preferable to use this over manually reading/writing our own files on the user's filesystem.

Originally posted by @dotproto in #41 (comment)

[wagnerand]

Comments have been removed.

[chrstinalin]

Not necessarily redundant -- information (ex. some add-on metadata) is still stored using the filesystem rather than globalState when, ideally, it should be the latter.

[wagnerand]

Ah, sorry I had understood from the original title that it is about comments.

[chrstinalin]

It technically was, since comments was the most relevant example (and what uncovered this in the first place), but its not the only application of it.