VPN-6330: More Linux static packaging fixes

[oskirby]

Description

To fix the missing fonts for Qt static builds, we need to rebuild Qt with fontconfig support (which also requires -system-freetype) and we patch up a missing libxcb-cursor0 dependency too while we are at it.

However! Because this just so happened to touch the Qt build scripts, we also needed to address some breakage in MacOS due to a busted homebrew install. In this case, I opted to just ditch homebrew and use conda because it's already a part of our build tooling anyways.

Reference

JIRA issue: VPN-6330

Checklist

• [ ] My code follows the style guidelines for this project
• [ ] I have not added any packages that contain high risk or unknown licenses (GPL, LGPL, MPL, etc. consult with DevOps if in question)
• [ ] I have performed a self review of my own code
• [ ] I have commented my code PARTICULARLY in hard to understand areas
• [ ] I have added thorough tests where needed

[oskirby]

Annoyingly, this was a negligibly small change to the Linux side of things - but unfortunately because I touched the Qt build scripts, I now have to deal with all the tech debt hiding in the MacOS build workers to get it going again.