Items gating listing in plugin catalog

[jeffgdotorg]

Thanks for addressing #1 . My colleagues identified a few other items that need attention; I'm breaking them into must-do and nice-to-do.

Must-do:

• NetBox versions newer than 3.4.99 not supported (see migrating to v4.0) #6
• Plugin / NetBox version-compatibility matrix missing from README #5
• Packages not published to PyPI #4
• No CI/CD workflows configured #3

Nice to do:

• __pycache__ incorrectly under version control