Fixed issues when scoop is installed to a separate directory from the apps folder (2nd PR since I made some mistakes)

[DelofJ]

Description

Changed the way Scoop behaves when it is installed in the global directory

Motivation and Context

Relates to https://github.com/ScoopInstaller/Scoop/issues/5939

How Has This Been Tested?

I made a clean installation of this modified version of Scoop with Tried to install, remove packages in the local/global directory And checked the Path environnement variable

Checklist:

• [X] I have read the Contributing Guide.
• [X] I have ensured that I am targeting the develop branch.
• [X] I have updated the documentation accordingly.
• [ ] I have no idea how to modify the scripts in the test folder according to the modifications I did
• [x] I (tried to) added an entry in the CHANGELOG.

Comments:

I previously made another PR but because of some mistakes I made while making my fork, I'm making a 2nd PR, here's the old one https://github.com/ScoopInstaller/Scoop/pull/5940