Group registration form

Historically, PyCon occasionally accepts group registrations via a spreadsheet. A PyCon member manually enters the spreadsheet data to create registrations at our registration vendor, CTE, for individual attendees.

CTE registrations are distinct from PyCon website accounts, but normally are associated with them via a `pycon_id` (e.g., the primary key of the user). This view allows a CTE registrar to bulk-create accounts (or find existing accounts) for individuals and retrieve their `pycon_id` values, so that individuals can log into the PyCon website later to update their registration information (t-shirt size, etc).

If an individual does not have a PyCon user account associated with their email address, one is created with an unusable password.