[FR]: easy integration tests with localstack

[alexeagle]

I should be able to manually run a test like so:

% bazel run //infrastructure/tools/aws:localstack
% docker run --rm -it -p 4566:4566 -p 4510-4559:4510-4559 localstack:bazel
% pytest 

to execute a test that expects to talk to AWS APIs, without any network connection.

We may also give guidance about using the Testcontainers library to make the test fixture bring up the containers when the test starts.

[peakschris]

Worth looking at rules_itest, which can probably help to orchestrate these 3 actions.