Add CI

[forgottosave]

Defines a Github CI, with the following requirements (see Issue #18):

• Add a CI run that builds using gcc as compiler a debug build
• Add a CI run that builds using gcc as compiler a release build
• Add a CI run that builds using clang as compiler a debug build
• Add a CI run that builds using clang as compiler a release build
• Run a clang-tidy build in debug
• Run a clang-format check
• All CI runs have to be run under fedora:latest
• Add cppcheck
• Investigate if CI builds using sanitizers make sense e.g. thread-, address-, undefined behaviour-, ...

[forgottosave]

On the sanitizers: I don't see why they would hurt at the moment, so I integrated them as well.
Example runs of the latest CI can be found here

[COM8]

Looks good! Found a few minor things.

[COM8]

Approved. Looks good!