Feat/cpp unittests

[SuperFola]

Adding proper C++ unit tests

Description

• Switches to C++20,
• updates the CI and removes a bunch of redondant/non C++20 compliant compilers,
• adds boost/ut to write unit tests (no dependance to other boost libs),
• adds unit tests using ut for the parser,

Closes #430

Checklist

• I have read the Contributor guide
• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation if needed
• I have added tests that prove my fix/feature is working
• New and existing tests pass locally with my changes