Clean up previous version install locations and check if other locations are still installed

Most appropriate sub-area of Processing 4?

PDE

Processing version

4.4.3

Operating system

all

Steps to reproduce this

#1022 left some todo's that did not block the PR but should be cleaned up at some point.

snippet

No response

Additional context

No response

Would you like to work on the issue?

I can, but happy for someone else to dive into