Frontend for registration summary

AS A Transplant Games registrant,
I WANT to see a summary of each registration and whether it's complete or not
SO THAT I know what else I need to do.

## Details
The cards for each registration on #60 should link to this.
Create a page to show the summary of the registration form indicating which fields have been filled in.
It should also show whether the form is complete or incomplete. If the form is incomplete, there should be a link to continue to the registration form to finish filling it out. If the form is complete, it should not be editable, and just show the summary.

## Acceptance criteria
Todo