Problem/Motivation
Follow-up to #1842718: Use new Transliteration functionality in core for machine names
As a follow-up to #567832: Transliteration in core, we now have a Transliteration class in Core.
@catch mentioned in #1314214: MySQL driver does not support full UTF-8 (emojis, asian symbols, mathematical symbols) we may want to transliterate filenames in core, so that we can have a database-level unique constraint on the URI field in the database. (However, this would presumably mean that transliteration of the field could not be optional).
Proposed resolution
Add a checkbox to the File system form to opt-in for filename transliteration. Transliteration for filenames will be disabled by default, because it's not useful for some languages like Japanese.