Some distributions provide python2 version of pylint package by default,
but all provide pylint for python3 in some package. Python 2 reaches
EOL in few months, so there's no reason to support it.
This prevents our scripts from being accidentally marked invalid due to
language changes between python 2 and 3. Also, newer pylint has nicer
output, that provides exact module filename straight in the warning.
Includes two small scripts: verify-bash.sh for running shellcheck, and
verify-python.sh for running pylint.
.pylint rc files is a default configuration file generated by
pylint 2.3.1, with one change (min-similarity-lines changed
from 4 to 10).