Small improvements in CodegenCppVisitor constructors

[iomaganaris]

• There is no purpose of having private constructors any more
• No reason for anything related to wrappers
• Remove mention of C code in logs

[tristan0x]

Less code !!! Very cool!

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01% ⚠️

Comparison is base (f180a2d) 70.19% compared to head (88c0ea3) 70.18%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1079      +/-   ##
==========================================
- Coverage   70.19%   70.18%   -0.01%     
==========================================
  Files         188      188              
  Lines       25630    25627       -3     
==========================================
- Hits        17990    17987       -3     
  Misses       7640     7640              

Files Changed	Coverage Δ
src/codegen/codegen_cpp_visitor.cpp	85.54% <ø> (-0.02%)	⬇️
src/codegen/codegen_cpp_visitor.hpp	100.00% <100.00%> (ø)
src/main.cpp	71.23% <100.00%> (ø)

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[bbpbuildbot]

Logfiles from GitLab pipeline #155527 (:white_check_mark:) have been uploaded here!

Status and direct links:

• ✅ spack_setup
• ✅ build:intel
• ✅ build:nvhpc
• ✅ test:intel
• ✅ test:nvhpc