Add support for PlayStation 4 and PlayStation 5

[grynspan]

Add support for PlayStation 4 and PlayStation 5:

• Audit our platform-specific code and add branches for the PlayStation 4 system software (mostly, but not entirely, the same as FreeBSD)
• Audit our platform-specific code and add branches for the PlayStation 5 system software (unsure if also FreeBSD-based?)
• Set up team workstations or VMs
• Set up CI jobs

[lin72h]

Thanks for making it happen. For my knowledge the Orbis OS for PS5 is based on FreeBSD 11

[grynspan]

The existence of this issue does not imply any specific work is being done. I filed it because os(PS4) is mentioned in the Swift repo, so there's been at least some effort toward building Swift for PlayStation.