Support `x86_64` and `i686` architectures

[lalten]

Actions using the amd64 and i686 arch will not actually use Qemu to run things. But it makes user's lifes easier by removing the need for special-casing no emulation builds.

The Dockerfiles use the https://hub.docker.com/u/amd64/ organization's containers as base.

Closes https://github.com/uraimo/run-on-arch-action/issues/93.

[lalten]

Ah, I just found out about https://github.com/uraimo/run-on-arch-action/pull/58... @uraimo feel free to pick this or the other one I guess.

[lalten]

While I was at it I added i686 support as well now. Maybe you'll find this PR easier to merge than #58 as it has fewer changes on top of latest master and supports more distros.

[lalten]

@uraimo friendly ping :bell:

[memark]

Would love to see this!

[thorrak]

I'd love to see this as well. I'm building for armv7 and aarch64 at the moment - being able to use a single action for x86_64 (and while I still support it, i686) would be great!

[lalten]

@uraimo I rebased this PR branch onto latest master and resolved all conflicts. Would be happy to hear your thoughts on this PR.

[maxexcloo]

Would love to use this also!