Add option to generate clients without Poetry

[dbanty]

Is your feature request related to a problem? Please describe.
Originally requested by @TMiguelT in #119 . The request is the ability to install a generated client with just pip (not Poetry).

Describe the solution you'd like
Instead of generating a pyproject.toml file with Poetry metadata, create a setup.py/requirements.txt to be used with Pip.

Describe alternatives you've considered
Additional common package management tools that might be worth adding support for are:

1. Pipenv
2. Flit
3. Twine

[pawamoy]

In my case, I simply want to generate the client code, not the packaging stuff (poetry/pip/else). I'm actually generating clients from several OpenAPI specs and merging them into one package. I'm more than OK dealing myself with the packaging configuration, especially since I have a template for this :) So having an option to skip all the packaging files would be nice as well :)

[multimeric]

True, for the most part the project metadata isn't that important to me since I'll just edit it, but having the dependencies listed is fairly important.

[multimeric]

Actually I wonder, if you add the [build-system] section (described here), which should be there anyway, it might just work automatically with PEP-517 compliant build tools ie recent setuptools.

[dbanty]

build-system will be included in clients generated by 0.5.0 so they are pip-installable. In a future version we'll add an option to generate with no metadata (and potentially other types of metadata).

[dbanty]

@Tsludorf I think generating with no metadata will also interest you, as you generate clients directly into your consuming projects.

[dtkav]

I added the setup.py from poetry build in my fork because I make heavy use of editable installs (pip -e) in order to mount this project into a docker container and iterate on it without needing to reinstall (or rebuild the container).

My workflow might be niche, so I'm happy to track it in my fork. I wanted to mention it in case:

1. Other folks know of a way to do editable installs like pip -e but with poetry
2. It's a useful user-story of why having a setup.py file would be helpful