Feat: Add linux/arm build support

[statickidz]

This PR updates the Docker workflow to support building and pushing images for both linux/amd64 and linux/arm/v5 architectures.

@debloper This functionality is untested and requires further verification for compatibility and successful image publishing.

[debloper]

Last I checked, this change wasn't sufficient (there were some toolchain deps needed for the build to pass on my Raspberry Pi).

But thanks for starting the fire again. This is on the roadmap & needs to get done.

EDIT: btw, if anyone reading this with technical knowhow and an ARM SBC, it'll be a massive help if you can run the setup script on your ARM board and share your progress here. One of the big limiting factor of making this feature work is avoiding edge cases, and I alone may not be able to spot them all; collective wisdom will be a great help.

[sunjam]

Any specific minimum requirements in terms of arm devices, such as ram?

[debloper]

Any specific minimum requirements in terms of arm devices, such as ram?

Rule of thumb (at least for minimum resource requirements):

• if it can run nginx, it can run xplex, BUT
• if it can run docker, it can most definitely run xplex