Enable PID file creation on WIN

Summary:
Enable PID file creation on Windows

• Add available WIN PID function
• Consider WIN32 in each relevant case
• Add new preprocessor definitions to suppress warning
• Update error message for generic OS

Co-authored-by: Jörn Röder <kontakt@joernroeder.de>

This is a backport of Core PR15456

Depends on D5775

Test Plan:

make check

Run the win64 build and run bitcon-qt

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D5776