[Tutorial] How to configure some runners as `x64` and others as `arm64`?

[skyzyx]

Similar but different from #991:

We have lots and lots of x86_64 AMIs and software, as I expect most people do. I also know that this module generates a Launch Template for spawning new instances.

I'd be interested in a tutorial (whenever, if ever this support exists) that explains how to set up scalable arm64 instances (assuming I/we have an arm64 AMI) so that certain jobs can specify the arm64 label and get one of those runners.

I would hate to ask you to duplicate the Launch Template for x86_64 vs. arm64 builds, but perhaps some kind of code-generation could simplify the process of maintaining consistency with small tweaks for each type?

[Makeshift]

Similar to #1282, #508 and #73 also.

[ScottGuymer]

There is now some documentation and support for different runner architectures here https://github.com/philips-labs/terraform-aws-github-runner#arm64-support-via-gravitongraviton2-instance-types