FxA module WIP
Fix IAC messaging
Rename FxUI to FxAccountsUI
Ensure that the UI flow always returns a result
Settings UI ready

Note - removed Persona UI from the settings app, rather than leave it
alongside the FXA UI. Merge was otherwise straightforward.

Conflicts:
	apps/settings/index.html
	apps/settings/style/settings.css
WIP commit to get helper feedback
another WIP commit, wiring up the logged-in screen
WIP commit: not reset password, change password.
WIP: l10n seems to work now