Add option to delete Library from the Hub

Please add an option to delete the library from the hub. The reality is this is required much more often than Unity wants to admit, so just embrace it and provide an easy way to do it.

Ideally the hub would not forget the platform setting when doing this, so we can avoid the all-too-common, "delete library" -> "open project from Hub" -> "Wait 2 hours for reimporting" -> "OMFG I didn't want the platform to be 'Standalone'" -> "Switch platform" -> "Wait another 4 hours for another reimport".

Just have a button somewhere that will wipe the library and open the project, so I can press it, leave for a few hours, and when I'm back I have the project with a fresh library and on the correct platform setting.