feat: add freebsd support

[0vf]

This PR will add full FreeBSD support to Rare

[TeknosQuet]

+1

[loathingKernel]

Thank you for your contribution!

A few general questions:

• Can we safely assume that FreeBSD == Linux in all possible use-cases in Rare?
• Have you checked if Legendary detects FreeBSD accordingly, if not, have you made a PR there or is it something that should be done?

One thing missing AFAICS is to include the required modifications in setup.py, requirements.txt and other relevant dist files completeness.

[0vf]

Legendary already works in FreeBSD OOTB, and in most cases, yes you can assume that FreeBSD == Linux (you can safely assume that freebsd == linux in the rare project continuing from now, as they both share the same window systems, desktop environments, standards, etc etc. the difference only really matters in compiled projects (eg. C, C++, rust), as freebsd is more similar to macos in that regard)

And also, thank you! I'll work more on this PR

[0vf]

Another small issue is that the pip package pyqt5 won't build on FreeBSD normally, so the use of the py39-qt5 package will be required

[0vf]

i think the PR is now ready, let me know if i've missed anything!

[loathingKernel]

Looks fine to me 👍

[Dummerle]

Thank you!