Enable debugging .NET applications in arm64 containers

[philliphoff]

Enable debugging of .NET applications in arm64 containers by installing new arm64 flavors of the .NET debugger as well as new in-container detection script to choose the correct debugger from a now larger matrix of platforms/architectures.

NOTE: This is intentionally limited to unblock users on arm64 (e.g. M1) Macs; there are external limitations to enabling arm64 support in general.

Related to #2884.

[karolz-ms]

The number of user OS - Docker daemon OS - container arch combinations makes my head spin a little, but your change looks good ☺️

[philliphoff]

@karolz-ms Yes and, admittedly, this doesn't address all of them (e.g. still need to investigate why arm64 alpine containers won't stop at breakpoints but otherwise run successfully). Still, this at least unblocks some M1 scenarios without (fingers-crossed) breaking all of the original amd64 combinations.