Fix jitpack build and add 'Use LogiVis as library' guide to readme

[danielbinder]

Add 'How to use LogiVis as library' right below the existing use section.

Include:

• How to use with gradle + jitpack (with code)
• How to add .jar manually to IntelliJ (with screenshot)
• "Or simply copy the code"

This probably requires a .jitpack folder/file and configuration file with at least Java 21 configured as jitpack does not work right now