feature: show list of apps being installed in the app store

[sbender9]

there's currently no easy way to see which apps are being installed and know when all are finished

[sbender9]

@tkurki should I just turn off the react/no-is-mounted rule for now?

[tkurki]

I find this a bit confusing

• hit a few [Install] buttons
• [Installing (n]] pill appears
• install finishes, the individual module lines show installed status
• [Installing (n]] pill remains and number stays at maximum install queue length??

I think the number should show the install queue length plus the one that is being installed and when done the pill should go away.

There is another confusion that is more obvious with this change: Installed list does not show the newly installed modules. Maybe it should? But that was already there...