Small developer improvements for Windows-based devs.

[ERYoung11]

Description

Some small improvements to make the development cycle better on Windows.

• requirements-dev.txt - pexpect doesn't work on Windows so I just put in a conditional to skip it on Windows. Also added sshtunnel since tests require it.
• setup.py - downloading psycopg-binary >= 3.0.14 on Windows only because Windows won't work without the binary version
• Some additions to DEVELOP.rst to give hints on how to do things on Windows and with VSCode debugging.

Checklist

• I've added this contribution to the changelog.rst.
• I've added my name to the AUTHORS file (or it's already there).

• I installed pre-commit hooks (pip install pre-commit && pre-commit install), and ran black on my code.
• Please squash merge this pull request (uncheck if you'd like us to merge as multiple commits)

[amjith]

Thank you! It is nice to know that the code base gets utilized in Windows environment.

[j-bennet]

@ERYoung11 We are now requiring a binary install in Windows, and I think it might be problematic sometimes:

#1413

Here, @dvarrazzo advised that depending on binary is not a good idea:

psycopg/psycopg#368 (comment)

You said that python install didn't work for you on Windows though. What was the problem?

Update: nevermind, the person actually had a source install of psycopg. Problem is solved.