jf_api now caches the list of users, only fetching new data if the cache
is more than 30 minutes old. Also remove the pointless tempJF with an
instance named auth_jf since jf_api can now handle multiple
authentications.
Pressing the user settings button brings up a list of all jellyfin
users, and allows you to add or change their stored email addresses.
Additionally, changed emails.json to use user ID instead of username.
The program automatically converts the file to the new format at start.
