Disable 'BINARY file' warning by default (#1441)

* Disable 'BINARY file' warning by default

Currently codespell prints a warning if it finds binary files in the tree.
This is annoying as many projects contain .git/.svn blobs, images, etc.
Disable the warning by default and let users enable it if needed.

Co-authored-by: Waldir Pimenta <waldyrious@gmail.com>

* Improve help message for the --quiet-level option

* Update _codespell.py

Co-authored-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Co-authored-by: Eric Larson <larson.eric.d@gmail.com>