Travel assistance to sydney please

* Tweaks help_text to indicate that travel assistance is to Sydney
* Includes the required migration

This migration doesn't change the DB so it's safe to apply with the system live.

Add the T&C and COC to the accept box

Link to the T&C and Code of conducts so people know what they are
accepting. Create this as a static link because i don't know how django
would accept this being something dynamic on the model.

This annoyingly creates a migration, but it's not a real change and
easier to accept it now than fight django forever.

Taking one out of PyCon's (US) book

We're lock-step with symposion, and upstream is dead.
Vendor it.