Include information for and allow managing of mod dependencies

[AlyxMoon]

There should be some way in the app to notify the user of the following:

• When a mod in the given profile is missing its required dependencies
• When a mod in general (in mod list section) is missing its required dependencies

Should provide an easy way for the user to download these missing mods. If this way in the context of a profile missing its dependencies, they should be automatically added to the profile.

When downloading from the mod portal, a dialog should display indicating any required/optional dependencies that exist for that mod, with the option to download all/any of them.

[AlyxMoon]

Mostly completed with recent merge. Did not address the mod portal part. Put off slightly because I want to implement a better UI for handling all things related to mod/dependency issues before I tackle this.