Merge `src/common` to `src/frontend`

[naftalimurgor]

• Move files from common/ to frontend/
• Adapt #include directives in common/
• Adapt #include directives for files previously in common/ to frontend/
• Adapt #include directives in client code from common/ for frontend/
• Update README.md in src/README.md

[lethal-guitar]

@naftalimurgor awesome, thanks a lot for the PR! Everything looks good from a first quick glance. Don't worry about the formatting, I can take care of that when merging.

[naftalimurgor]

Hello @lethal-guitar

Sounds great! Please let me know of any further feedback.

[lethal-guitar]

@naftalimurgor no further feedback, nicely done, thanks again! I did just one minor change, which was to alphabetically sort the list of files in the CMakeLists.txt - I try to keep it always sorted for easier overview.

[naftalimurgor]

@lethal-guitar Awsome! Will always do so. Much appreciation for adding me to the list of Authors 🚀

[lethal-guitar]

@naftalimurgor my pleasure 🙂