Registration Form: allow users to cancel their registration

[pferreir]

There's already backend code for this (Registration.withdrawn), we have to make it available from the interface. It should be configurable.

[SebastianLopienski]

It would be also good to allow event managers to withdraw an application/registration (e.g. one the person withdraws by email to event organizers)

[SebastianLopienski]

To add: Ideally, I would like to be able to:

• remove a registration (e.g. for double registration)
• withdraw a registration (when a person asks for it - see above)
• reject a registration
• accept a registration

First three actions are all different, and should result in a different state.

[brabemi]

Hi, in my fork i added withdraw button with confirmation popup into registration detail view. Behavior is the same as for modify button.

I will think about how to add withdraw action for event managers

[bpedersen2]

@brabemi : Would you mind to create a pull request?