filename standardization on upload

[StudioZut]

When content editors upload images and pdfs etc, ensure that files are renamed to avoid whitespace, capitalization, and special characters -- basically anything that isn't a-z or 0-9 or a dash (an underscore is also ok if that's a nuisance to avoid).

Additional request -- can we force files to have a name that isn't just numbers? To avoid a bunch of files named 01.jpg

Much of this might be functionality added to core as of 10.2. See https://www.drupal.org/node/2972665

Dev tasks:

• Enable transliteration at admin/config/media/file-system and check all the boxes under it.
• Export that config back to the wri_sites repo, and add an update hook for it.
• The "Name" field on an image upload is already required. See if you can add additional quality check to also ensure the name contains something other than numbers and the extension (so no "01.jpg").
• On media save, try to update the filename to be the transliterated cleaned-up version of the media "Name" field.
• Make sure this doesn't interfere with the "_1", "_2" suffixes that you get if the name of the post-transliterated file already exists.