Rename internal function array_or_string to lines
concat+lines: Already let File::Slurp do the chomp
Simplify lines() to a one-line ?: instead of if/else
Move lines() to new Run::Parts::Common module

This adds a new test and run requirement on Exporter::Easy.
Remove no more needed example dependency comments
Fix out of sync version in POD of Run::Parts::Perl
Replace functionality of lines() with lines() in Run::Parts::Perl
Replace functionality of lines()+chomp with new chomped_lines()
Clean up POD