Create multi-region setup for multi-runners

[amicotacleeng]

We have a scenario where in our company there is a need to run a set of runners in a specific region for test execution.
In multi-runners setup every resource is set regionally and it would be great if there was a possibility to set a new group of runners using multi-runner setup that would be created in a specifically whosen region using labels.

[Brend-Smits]

Our organization would definitely also benefit from multi region setup. I'm not sure yet how challenging it would be to support this.
Does anyone have capacity/interest to start development on this?

[stuartp44]

as above!

[bogdankrasko]

@amicotacleeng @Brend-Smits @stuartp44 A multi-region setup can be achieved by following these two PRs:
#5099
#5123

We have tested this in our organization, and it enables runner groups across multiple regions. It also allows the use of a separate GitHub App for each region or repository to help avoid rate limiting.

I would appreciate it if someone could review and merge these changes.