feat: add multiple zones to a system

[jeremyw24]

Is your feature request related to a problem? Please describe.
Adding zones to a system one at a time is time consuming.

Describe the solution you'd like
Systems: Allow user to select multiple zones from the drop down list and apply at once.
Zones: select multiple systems from a drop down list to add them to zones.

[jeremyw24]

I am happy with this solution.