Add support for string matches

[cloutierMat]

Motivation

This pr adds support string utility matches. The functionality itself was fairly straightforward but some changes to StringLiteral were required to fully support regular expressions. Notably we were only allowing certain characters to be escaped in string literals, while aws accepts anything. No tests seemed to depend on the escaped character restriction, but it should be safer to run a full suite of localstack tests to ensure this does not create any unforeseen regressions.

Since localstack has gone through a big code restructure since last time this code was change, I have had to update conftest and the main.yml configuration to be inline with latest development

[bentsku]

LGTM! The changes look safe to me, and it seems we're having the same behavior as the official VTL library for this. Good investigation and fix 🕵️

The changes to the tests/CI looks good too, I think we might be able to not install the test target instead of runtime (it's a lot more) but only add localstack-snapshot to the list of extra_requires in setup.py? Might be worth giving it a try 😄
I suppose we should switch it to pyproject.toml at some point soon.

Also, we should probably already bump the version in setup.py and update the changelog in the readme, if possible. Then, we're good to go! 🚀

[cloutierMat]

I think we might be able to not install the test target instead of runtime (it's a lot more) but only add localstack-snapshot

Good idea, I will explore on that.

Also, we should probably already bump the version in setup.py and update the changelog in the readme, if possible. Then, we're good to go! 🚀

👍