Python wheels support

[proway2]

Since eggs are deprecated https://setuptools.pypa.io/en/latest/deprecated/commands.html#bdist-egg-create-a-python-egg-for-the-project it makes sense to add support for wheels.

Proposed config file:

stacks:
  default: "scrapy:2.8"

projects:
  dev:
    id: 123
    requirements:
      file: requirements.txt
      wheels:
        - ../path/to/some-0.1.0-py3-none-any.whl
        - other.whl
  prod: 456

requirements:
  file: requirements.txt
  wheels:
    - /absolute/path/to/some.whl

[proway2]

Or may be it's better to add support for setting a path to a folder that contains setup.py?

[Gallaecio]

We could support both. But I think an initial implementation expecting a pre-built wheel file makes sense.

[proway2]

Agree, let's get it done step by step.