PostCopy Action Improvements

[atroiano-glue]

Added auto-dir creation for PCA
- Checking File Existence
- Checking existing directory existence
- Added related test

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 3 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@fef5413). Learn more about missing BASE report.
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/opentaskpy/remotehandlers/sftp.py	83.33%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #115   +/-   ##
=======================================
  Coverage        ?   89.07%           
=======================================
  Files           ?       21           
  Lines           ?     2471           
  Branches        ?        0           
=======================================
  Hits            ?     2201           
  Misses          ?      270           
  Partials        ?        0           

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[atroiano-glue]

Adam - This is ready for your review :)