feat: Enable macos desktop

[ymauray]

Description

This pull request enables macos desktop for quickgui.

This is still early work, so they're might be some edges cases that will need investigation.

Type of change

• [X] New feature (non-breaking change which adds functionality)

Checklist:

• [X] I have performed a self-review of my code
• [X] I have tested my code in common scenarios and confirmed there are no regressions
• [X] I have added comments to my code, particularly in hard-to-understand sections
• [X] I have updated and committed pubspec.yaml and pubspec.lock
  • flutter pub get

What is has been tested on

• mac book air M2, default macos terminal

What works

• Getting the list of available OSes and their versions from quickget
• Starting the download, and monitoring its progression
• Listing availables VMs
• Starting and stopping a VM through quickemu
• Connecting to a VM via SSH using the default macos terminal
• Partially or completely deleting a VM

What has not been tested

• Downloading and running any distro which does not have "ubuntu" in its name

What does not work

• Packaging a dmg file. I need to look into that.

[ymauray]

I fixed the icons, hopefully.

[gregpalaci]

Sorry to reopen I'm 99% way for compling on arm64 mac but getting a weird error. I build with Dart and quickemu is in the Path.... any tips?