Add arm64 artefacts to dotnet autoinstrumentation container.

[Mpdreamz]

This will allow the operator to auto instrument dotnet applications on arm64 containers. (Including k8s on OSX M1/M2/M3 etc)

Validated manually as part of Elastic's distribution of OpenTelemetry .NET

elastic/elastic-otel-dotnet#155

CC @Kielek & @RassK who did the bulk of the work actually creating the artefacts 🙏

[Kielek]

1. As I know, there is a possibility to have separate images for architectures (arm64/x64). It could reduce image size to download. I am not telling that it is mandatory for this PR.
2. It will not work without additional changes on the operator side. See code around

   opentelemetry-operator/pkg/instrumentation/dotnet.go

   Lines 48 to 51 in 5497a49

   	const (
   	dotNetRuntimeLinuxGlibc = "linux-x64"
   	dotNetRuntimeLinuxMusl = "linux-musl-x64"
   	)

[Kielek]

Please document changes around lines 7 and 8 - CORECLR_PROFILER_PATH

[swiatekm]

It doesn't look like this fully addresses the issue. The operator will still set the CORECLR_PROFILER_PATH to the x64 path.

I think a clean way to implement this would be:

1. Make the image multi-platform, changing the path to just linux. Add a linux-x64 symbolic link for backwards compatibility.
2. Use the new path when injecting instrumentation.

For 1, you just need to add the built-in ARG TARGETARCH and use this variable in your urls.

[Mpdreamz]

Just a note that I will get back to this PR either this or next week.