Split declaration and implementation of CapioFile class

[marcoSanti]

This commit refactors the CapioFile class. In particular:

• Splits class declaration and class implementation;
• Resolves a bug in CapioFile::waitForData method, for which the condition variable predicate condition was reversed. It also introduces tests to check for this specific issue on both CapioFile::waitForData and CapioFile::waitForCommit;
• Introduces several new tests on the CapioFile class to improve coverage and protect against regressions;
• Fixes an issue in the CI/CD for which coverage was computed on the test files as well. Now they are excluded ensuring that coverage reflects only the state of the project runtime targets.

[codecov]

Codecov Report

❌ Patch coverage is 93.62745% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.59%. Comparing base (6c2814b) to head (0b0e8e0).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
capio/server/src/capio_file.cpp	93.59%	0 Missing and 13 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #211      +/-   ##
==========================================
+ Coverage   62.50%   64.59%   +2.09%     
==========================================
  Files          76       73       -3     
  Lines        3334     3161     -173     
  Branches     2059     1965      -94     
==========================================
- Hits         2084     2042      -42     
+ Misses        959      372     -587     
- Partials      291      747     +456     

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[GlassOfWhiskey]

LGTM