Add filter for removing subscribed communities from Local view

[pickscrape]

Is your feature request related to a problem? Please describe.

As I subscribe to more communities, it becomes more difficult to find new ones that I might be interested in.

Describe the solution you'd like

It would be nice to be able to filter out communities that I've already subscribed to from the Local view. I suppose having the same for the Everything view would also be useful in a similar way.

Describe alternatives you've considered

Browsing the list of communities is another way (though I don't think it filters out subscribed communities either), but browsing Local also provides additional context about what the communities are about, in addition to automatically showing communities that have recent activity first.