feat: unify application start by using a launcher

[jorgepiloto]

This pull-request solves #906 by adding a launch_stk method in the extensions subpackage.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 95.55556% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.58%. Comparing base (2176773) to head (0f704c3).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
src/ansys/stk/extensions/launcher.py	95.55%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #928   +/-   ##
=======================================
  Coverage   89.58%   89.58%           
=======================================
  Files          67       68    +1     
  Lines      189104   189149   +45     
  Branches     1413     1423   +10     
=======================================
+ Hits       169412   169457   +45     
+ Misses      19278    19276    -2     
- Partials      414      416    +2     

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