chore: add describe info for python2

[stasadev]

The Issue

It's a bit weird to see a stopped python2 service in ddev describe.

How This PR Solves The Issue

Adds explanation to ddev describe.

Manual Testing Instructions

ddev add-on get https://github.com/ddev/ddev-python2/tarball/refs/pull/REPLACE_ME_WITH_THIS_PR_NUMBER/head
ddev restart
ddev exec python --version
ddev exec pip --version
ddev describe

Automated Testing Overview

Release/Deployment Notes