feat: adding a setting for a tracked directory

[artushin]

Adding a setting to specify a directory to track. Useful for when you have a monorepo with a docs subdirectory that you want to contribute to using Obsidian but want to track the rest of the repo in your usual git flow.

Untested, so I'll make this a draft PR, fix any bugs that crop up and swap to a real PR when it's ready.

If not interested in merging in the setting just lmk and I'll close the PR.

[Vinzent03]

Great that you try to start working on this feature. If manageable, I would try to allow multiple directories to be tracked. I suppose this is not much harder than a single directory, but allows more individual setups.