ci: Add pre-commit checks

[ghost]

Signed-off-by: david-doit-intl david@doit-intl.com

[stepanstipl]

Thanks @david-doit-intl .

1. The doc improvements are nice 👍

2. The test coverage 👍 - it would be nice to expose this somehow more visibly and check that we're not getting worse with any single commit :)... but this is a good start.

3. I have some concerns about the pre-commit func. In particular:

• a) It expects/installs stuff on host system which I find a bit dangerous, and cluttering - ie. pre-commit is python, but will install go (such as checkmake). I didn't dig into this too much, but as someone who's trying to control what and in which way is installed on my system, this makes me somewhat uncomfortable. I expect this can "break" in many ways, depending on your OS and other bits.
• b) Reproducibility of the builds - because of environment dependencies, and referencing master versions of those hook repos., we might get different results.
• c) Quality and usefulness of the individual hooks - like for example the checkmake one doesn't seem to do much.

Overall it seems like a potentially complex system with a lot of dependencies.

Also re. the build reproducibility, I would like to keep easy parity of being able to execute all tests via make, both locally and in ci. There's a pattern, which I like (and would assume we have proper build image, currently golang one). This allows you to easily run any make step both locally and/or from inside the container), as well from outside by prefixing it with docker-.

docker-%:
	docker run -it --rm -e TF_VAR_project $(DOCKER_IMAGE) $*

Finally, I really like the idea of pre-commit (just not the implementation so much), and realised how tired am I of writing same CI bits over and over again :). In longer-term, I started looking into nix and it's shell functionality (check
https://github.com/hashicorp/waypoint/blob/main/shell.nix for an example how this can be used) as a better option to purely docker based reproducible dev/build environments. And considering building a shared library of "CI" scripts... but this might take a while.

So on a pragmatic note, the results are good -> let's merge this as it is 👍 and improve later :).