Add installation progress bar to dock icon

[senmu]

Closes #17

Uses suggested DockProgress to display a progress bar overlay on top of the dock icon as an Xcode is downloading.

Successor to #85. A new overallProgress has been pulled up to track the downloading and the unarchive portion of installing an Xcode. Within the overallProgress the following weights are applied:

• 90% of the overall progress is allocated to the download
• The remaining 10% is allocated to the unarchive step
  • This is tracked in a binary fashion (incomplete or complete) as no progress is provided in any sort of callback during the unarchive process

Below are some previews:

During download

During unarchiving

During the post-installation/finishing steps

These final steps require user interaction so no new child Progress objects were created to track these. However, you can see that once it gets here, the progress bar is gone.

[senmu]

I needed to update the CI workflow to use Xcode 14.2 via b6e654c as building failed (see 622fac6) on 13.2.1

[MattKiazyk]

Thanks a bunch @senmu (sorry for the late response)