FEAT: Automatically figure out the architecutre being ran on

[samip5]

Now that there's arch-type input, it would be nice if that actually happened behind the scenes like many other actions behaves.

[elitistphoenix]

I'd like to add a +1 too. In a multi-arch cluster having to pin our runners to a specific arch rather than let then run on whatever Karpenter thinks is best and cheapest is a bit frustrating.