Add a fix script that fixes invalid email addresses if they can be
fixed, otherwise they're deleted.
For a long time we didn't have any email validation, so we ended up with
a lot of invalid email addresses containing typos or other random garbage.
This tries to fix the most common typos when possible, otherwise the
email address is deleted.
In many cases the user created two accounts, one with a typo in the
email and one with the correct email. In these cases we can't fix the
invalid email, so we just delete it.
21747e1f8e