Enable clang-tidy in linalg wrappers

[knarfnitram]

Description

As pointed out in #403, we do not apply the style format to the files:

• 4C_linalg_vector.hpp/cpp
• 4C_linalg_graph.hpp/cpp

This means that the functions should be renamed within the code base.
Clang-Tidy suggests appropriate function names, which are inline with our style-format. As an example, this will look like:
graph.Comm() -> graph.comm() or
get_ref_of_Epetra_Vector -> get_ref_of_epetra_vector()

Possible Solution and Definition of Done

• Remove // NOLINTBEGIN(readability-identifier-naming) at the files
• Run clang-tidy
• Rename the corresponding functions as suggested by clang-tidy within all appearances

Interested Parties

@amgebauer @mayrmt