feat: Modernize PVRTexLib dependency

[Jklawreszuk]

PR Details

My PR updates PVRTexLib to the latest version and adds a shared library for Linux. In the process, I refactored PVRTWrapper and removed methods that were not used anywhere.

~Note : To be honest I don't know how to test the changes yet so my changes may not work properly~ Done

Types of changes

• [x] Docs change / refactoring / dependency upgrade
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• [ ] My change requires a change to the documentation.
• [ ] I have added tests to cover my changes.
• [ ] All new and existing tests passed.
• [ ] I have built and run the editor to try this change out.

[Jklawreszuk]

PR should be ready for review. I made simple program to test all the methods and it works as expected :) Perhaps it would be also useful to rewrite the current TextureConverter tests (project currently does not work) Program.txt

[Eideren]

Thanks !