move PATH fixing out of get_pipsi

[RonnyPfannschmidt]

followup to #148

we should strive to have a simple and straightforward get_pipsi script
as such the shell script fixing should move to a module in pipsi
(as that is usable after installation)

[cs01]

Well that was fast. What changed your mind back?

[RonnyPfannschmidt]

@cs01 the path fixing should still happen, this is about the code location - until someone demonstrates its a grave mistake im on board with it

[RonnyPfannschmidt]

@cs01 i decided to make this issue right when i decided your pr is good to go, because the feature works now ^^ the rest is details that can happen later

[cs01]

Sounds good. I'll see if I can put a PR together and some unit tests (for the other issue you made).

[RonnyPfannschmidt]

@cs01 thanks, take your time, i have another pr i want to merge, then i will apply black/pre-commit to the repo and take a look at releasing