Introduce C++20 target to avoid usage of deprecated constructs

## Brief feature description

Some constructs like `std::result_of` where deprecated in C++17 and are no longer supported with C++20. A c++20 CI target would help avoiding such constructs right from the beginning so that iceoryx can be used also in C++20 projects.

At the moment GTest 1.10 is not working with C++20. Either we use a more modern version or skip unit tests on that target for the time being.
This should be alright since we are aiming to use iceoryx in C++20 projects as a library. So the test should not be required.

Start by locating the CI configuration and existing compiler-standard targets, then check how GTest 1.10 is integrated. Add a C++20 target that detects unsupported deprecated constructs; the target should build iceoryx as a library, with unit tests either working with a newer GTest or explicitly skipped as described.

Written by the indexing model from the issue text.