Add auxiliar InternalWriter

[juanlofer-eprosima]

Move already existing helper class from Fast-DDS-spy repo so that it can be reused in other tools.

[EugenioCollado]

LGTM with green CI

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes missing coverage. Please review.

Project coverage is 37.83%. Comparing base (f6fec3c) to head (fc5e554).

Files with missing lines	Patch %	Lines
...cipants/src/cpp/writer/auxiliar/InternalWriter.cpp	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #138      +/-   ##
==========================================
- Coverage   37.86%   37.83%   -0.03%     
==========================================
  Files         152      153       +1     
  Lines        6956     6961       +5     
  Branches     2764     2765       +1     
==========================================
  Hits         2634     2634              
- Misses       2937     2942       +5     
  Partials     1385     1385              

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