docs: Add support and build instructions and workflows for arm64

[michaelbrewer]

Is your feature request related to a problem? Please describe.

Now that arm64 architecture is official for lambdas, we should ensure Powertools works perfectly well and have a guide on how to take advantage of this feature via SAM and CDK.

Describe the solution you'd like

Update docs and test automation to include arm64

Describe alternatives you've considered

Additional context

[heitorlessa]

Ref GrahamDumpleton/wrapt#198 as pointed out by @eldritchideen, since we depend on X-Ray SDK this won't likely be possible with SAM CLI (maybe via Makefile but suboptimal), but a custom Lambda Layer.

[eldritchideen]

I have also commented on what appears to be the root cause in the Pip builder that SAM uses to package the dependencies here. aws/aws-lambda-builders#302

The wheel for wrapt gets built correctly, however as the file name has "linux" rather than "manylinux" it is rejected as not compatible.

[eldritchideen]

This example repo shows how to work around the issue of Arm dependencies that require sdist builds with C extensions failing by packaging them in a layer.
https://github.com/eldritchideen/arm-python-lambda-example