Feature request: SACs assigned to ACs, can reassign ACs

[racheljsmart]

Currently, if the SAC Assignment is set to Area Chairs in the request form, the SACs are assigned to ACs and cannot modify AC assignments. There are some large venues with this configuration that would benefit from being able to delegate AC assignment modifications to SACs.

[melisabok]

The only constrain here is that the SAC can reassigned ACs from their pool.

And only assigned ACs that are assigned to the SAC.