[#23719] Add notifiers

[emiliocuestaf]

This pull request introduces a notification system for alerts in the statistics backend, allowing users to associate external scripts with alert triggers.

Notifier Infrastructure

• Added a new notifier system, including the Notifier, ScriptNotifier, and NotifierManager classes in Notifiers.hpp, enabling alerts to trigger external scripts asynchronously.
• Included script validation and execution logic, supporting both Windows and Linux platforms.

[codecov]

Codecov Report

❌ Patch coverage is 41.37931% with 51 lines in your changes missing coverage. Please review.
✅ Project coverage is 47.05%. Comparing base (a580c10) to head (b4062bd).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ude/fastdds_statistics_backend/types/Notifiers.hpp	47.50%	17 Missing and 4 partials ⚠️
src/cpp/database/database.cpp	27.58%	16 Missing and 5 partials ⚠️
src/cpp/StatisticsBackend.cpp	44.44%	2 Missing and 3 partials ⚠️
src/cpp/StatisticsBackendData.cpp	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #292      +/-   ##
==========================================
+ Coverage   46.72%   47.05%   +0.32%     
==========================================
  Files          53       54       +1     
  Lines       16993    17092      +99     
  Branches     7088     7129      +41     
==========================================
+ Hits         7940     8042     +102     
+ Misses       4547     4514      -33     
- Partials     4506     4536      +30     

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