Add new has-command output parameter

[xt0rted]

This builds on #136 and adds a new has-command out parameter that can be used to check if the job should continue or not.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.90%. Comparing base (3a57d7f) to head (f2335b4).
⚠️ Report is 1319 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #137      +/-   ##
==========================================
+ Coverage   86.74%   86.90%   +0.15%     
==========================================
  Files           5        5              
  Lines          83       84       +1     
  Branches       11       11              
==========================================
+ Hits           72       73       +1     
  Partials       11       11              

Flag	Coverage Δ
unittests	86.90% <100.00%> (+0.15%)	⬆️

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