chore: add dev, docs and test dependcies to Poetry

[gruzewski]

Update Poetry with new groups

Add Poetry group dependencies for development, documentation and testing. This change gathers dependencies declared in different files (requirements.docs.txt, README.md, test.yml), making creating a local development environment easier when contributing.

This is a no-op as all groups are declared optional and existing installation methods are preserved.

Testing:
I built and ran Kapitan's Docker container locally before removing the compiled directory.

➜  kapitan_fork git:(update_dev_poetry_deps) docker build -t kapitan:update-dev-poetry-deps .                                                                                      git:(update_dev_poetry_deps|⚑1)
[+] Building 1.3s (21/21) FINISHED
 => => naming to docker.io/library/kapitan:update-dev-poetry-deps
➜  kapitan_fork git:(update_dev_poetry_deps) cd examples/kubernetes
➜  kubernetes git:(update_dev_poetry_deps) rm -rf compiled                                                                                                                        git:(update_dev_poetry_deps|⚑1)
➜  kubernetes git:(update_dev_poetry_deps) ✗ docker run -t --rm -v $(pwd):/src:delegated kapitan:update-dev-poetry-deps compile                                                  git:(update_dev_poetry_deps|-92⚑1
Rendered inventory (0.18s)
Compiled removal (0.00s)
Compiled busybox (0.06s)
Compiled labels (0.06s)
Compiled minikube-nginx-jsonnet (0.13s)
Compiled minikube-nginx-kadet (0.06s)
Compiled minikube-mysql (0.16s)
Compiled minikube-nginx-helm (0.16s)
Compiled minikube-es (0.32s)
Compiled all-glob (0.53s)
➜  kubernetes git:(update_dev_poetry_deps) git status                                                                                                                              git:(update_dev_poetry_deps|⚑1)
On branch update_dev_poetry_deps
Your branch is up to date with 'origin/update_dev_poetry_deps'.

nothing to commit, working tree clean

[MatteoVoges]

Hey @gruzewski ,
thank you for your contribution.

Please make sure that the other workflows like building the docker image or building the documentation itself doesn't fail like with #929 .

@ademariag @gburiola @ramaro @uberspot Is there a way we can test this beforehand? Can you unlock the tests withheld from the public? 😆

[gruzewski]

@MatteoVoges sure thing. I will build it (which I believe I have done it already). I will see if I can also test Github Actions with act but if there are a lot of secrets to provide, it might difficult to do.

[gruzewski]

I tested the building Docker image, and it looks good.

[uberspot]

lgtm

[Moep90]

@gruzewski can't we, using poetry, get rid of the venv documentation?
AFAIK Poetry already creates a venv in the background, right?

[gruzewski]

@Moep90 we could, but I am pretty sure some people still prefer to use old pip (which doesn't require installing poetry and is much faster). I suggest keeping both for now and revisiting it another time.

[MatteoVoges]

@gruzewski If you rebase and solve the conflicts with running poetry lock --no-update again, we can merge.