Add an option to silence collectstatic clashing files warnings

[Justin McCammon]

Due to the changes introduced in #24890 in 1.9, if you use an app like Grappelli which overwrites portions of the admin you get numerous warnings every time you run collectstatic. There should be an option to silence these warnings since there are times where you would knowingly want to overwrite files and don't wish to see the warnings.

Example of warnings:

Found another file with the destination path 'admin/js/jquery.init.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/calendar.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/prepopulate.min.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/inlines.min.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/actions.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/actions.min.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/core.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/collapse.min.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/inlines.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/prepopulate.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/collapse.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/timeparse.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/urlify.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/SelectFilter2.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/SelectBox.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/admin/RelatedObjectLookups.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/admin/DateTimeShortcuts.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/vendor/xregexp/xregexp.min.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/vendor/xregexp/LICENSE-XREGEXP.txt'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/vendor/jquery/jquery.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.
Found another file with the destination path 'admin/js/vendor/jquery/jquery.min.js'. It will be ignored since only the first encountered file is collected. If this is not what you want, make sure every static file has a unique path.

[Tim Graham]

Switching management commands to use logging (#21429) might be one way to solve this.

[Claude Paroz]

You can silence those with verbosity=0, can't you?

[Chris Frisina]

Yes, but doing so with ./manage.py collectstatic -v 0

also would not provide the final print of the status of the collectstatic, such as

0 static files copied to '/Users/dejanew/Dropbox/dev/MST/server/static', 833 unmodified.

There is a potential to change the level of the display to 2, but that would also be likely hidden for the majority of the users.