The new `enforce_canonical_emails` site setting ensures that emails in the
canonical form are unique.
This mean that if `s.a.m+1@gmail.com` is registered `sam@gmail.com` will
not be allowed.
The commit contains a blanket "tag strip" (stripping everything after +)
it also contains special handling of a "dot strip" for googlemail and gmail.
The setting only impacts new registrations after `enforce_canonical_emails`
The setting is default false so it will not impact any existing installs.
Zeitwerk simplifies working with dependencies in dev and makes it easier reloading class chains.
We no longer need to use Rails "require_dependency" anywhere and instead can just use standard
Ruby patterns to require files.
This is a far reaching change and we expect some followups here.
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
