Improve devcontainer experience

[chrschorn]

Starting from a fresh clone, I faced these issues inside a no-cache build of the devcontainer:

isort is missing when you try to run python main.py -> I added it to the poetry dev dependencies

pre-commit run doesn't work out of the box (see screenshot below). This is because the way the devcontainer is setup is a little odd:

• At build time, the source folder ("nicegui") is copied to the current directory and then installed

  nicegui/.devcontainer/Dockerfile

  Lines 30 to 31 in 3fcfac6

  	COPY nicegui pyproject.toml poetry.lock README.md ./
  	RUN poetry install --all-extras

  With that, you end up with a copy of the nicegui/ folder contents in / which is registered as a Python module (due to the poetry install), leading to a circular import. The source files are not needed to setup the dependencies in the container, which can be achieved with poetry install --all-extras --no-root and just the poetry.lock.
• The .devcontainer has an extra }, causing this to never run:

  nicegui/.devcontainer/devcontainer.json

  Lines 38 to 39 in 3fcfac6

  	"remoteUser": "vscode",
  	"postCreateCommand": "poetry install --all-extras"

  I removed the } and now it's correctly executed. Technically the devcontainer dockerfile wouldn't need to run poetry at all now which is worth considering.

Something else I noticed but didn't want to touch because I don't know how it impacts CI/CD: CONTRIBUTING.md mentions autopep8 --max-line-length=120 --in-place --recursive . It would be nice if this was included in pre-commit to not have to run multiple commands before commit/push.

[rodja]

Thanks for this PR @chrschorn. I tested the setup and it works as expected.

[rodja]

Something else I noticed but didn't want to touch because I don't know how it impacts CI/CD: CONTRIBUTING.md mentions autopep8 --max-line-length=120 --in-place --recursive . It would be nice if this was included in pre-commit to not have to run multiple commands before commit/push.

You are totally right! Would you like to create a pull request for this?