Event admins can invite people to events via their email or phone number

The process would be:

- Create event

- Click "invite"

- Add emails and phone numbers (there will be integration with contacts apps to make this easier)

- Click "send emails" or "send SMSs" to send bulk email/SMS to guests from the admin's email address/phone number

- Guest details are added to the event, saying "invited"

- The email/SMS contains a link the guest can click through to get to the event. If they aren't logged in, or don't have the right email/phone number configured, they'll need to input it