Add scripts/get_maintainer.pl

A script to parse file pattern information in MAINTAINERS
and return selected information about a file or patch

usage: scripts/get_maintainer.pl [options] patchfile
       scripts/get_maintainer.pl [options] -f file
version: 0.14

MAINTAINERS field selection options:
  --email => print email address(es) if any
    --git => include git "*-by:" signers in commit count order
    --git-chief-penguins => include (Linus Torvalds)
    --git-min-signatures => number of signatures required (default: 1)
    --git-max-maintainers => maximum maintainers to add (default: 5)
    --git-since => git history to use (default: 1-year-ago)
    --m => include maintainer(s) if any
    --n => include name 'Full Name <addr@domain.tld>'
    --l => include list(s) if any
    --s => include subscriber only list(s) if any
  --scm => print SCM tree(s) if any
  --status => print status if any
  --subsystem => print subsystem name if any
  --web => print website(s) if any

Output type options:
  --separat...