User banning rework

At the moment we have user banning which is pretty not-natural, so we'll need to rework it.

1. First of all the main window should contain a search box and Add button as it does right now. But while choosing someone and pressing Add, a dialogue window should appear that allows to input the amount of days the user should be banned, the 'eternal damnation' checkbox and the Reason of Ban; after pressing Save, the dialogue is closed and a new victim can be viewed in the grid of doomed.
2. The grid at the main page should contain users that are banned already. When you just open the window, all the banned users should be there.
3. Moreover the grid rows should contain a manipulation buttons as the last column: Removing (unbanning) the users and editing the ban properties.
4. Also, the editing of the ban properties window should appear when admin doubleclicks the row.

This story is mostly for front end, back end will be changed in the future with a different story.