In newer Embers jQuery is removed. There is a `find` but it only returns
one element and not a jQuery selector. This patch migrates our code to a
new helper `queryAll` which allows us to remove the global.
allowEmails used to always be set to true and did not use
can_invite_via_email, which checks for enable_local_logins.
It was a problem because on sites with local logins
disabled users were allowed to enter email addresses, but
received a generic error "error inviting that user".
This is where they should be as far as ember is concerned. Note this is
a huge commit and we should be really careful everything continues to
work properly.
