[Feature] Editable filter names

[sleetx]

The filter dropdown allows you to modify existing filters, either with new conditions, or to delete a filter entirely.

I propose allowing filter names to be editable - so we can change the name of the filter itself, rather than only modify the conditions. Since the filter list is shown alphabetically, this is also a way for users to update where on the list their filter appears.

To indicate the filter name change ability, let's add a new "pencil" icon next to the "save" and "delete" icons.