armel: run on ubicloud

[Habbie]

It's important to note that this breaks armel builds on forks. I suspect (but have not tried) that those forks can make them work by creating a runner group called ubicloud-standard-2-arm that will then run on GH runners and use qemu.

[Habbie]

those forks can make them work by creating a runner group called ubicloud-standard-2-arm that will then run on GH runners and use qemu.

I was wrong about this.

[Habbie]

perhaps https://stackoverflow.com/questions/71961921/specify-runner-to-be-used-depending-on-condition-in-a-github-actions-workflow

[Habbie]

second commit makes fork use qemu instead of failing