Add Grid to Manage Staff Page

[conzty01]

Is your feature request related to a problem? Please describe.
In the current implementation, it can take a bit to remove a large number of RAs from a Res Hall's staff.

Describe the solution you'd like
It might be nice to update the Manage Staff page so that users can select staff members and delete them en masse. Once one or more rows are selected in the grid, additional buttons can be made available that allow the user to delete, add points, or change the auth level without having to go into each RA's details individually.

Additional context
This might also make it easier to remove staff members at the end of each academic year.