perl/modules/.gitignore: Add META.json, MYMETA.json

ExtUtils::MakeMaker 6.57_07 and later generate META.json and
MYMETA.json in addition to META.yml and MYMETA.yml.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Remove redundant .gitignore, .hgignore files

This is all taken care of by the root .gitignore file.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>