New Registration 3 export function

New feature for direct import of registrations into the CAS Scoring app from the website casscoring.com.

Matches that are split across multiple days and have the same export group set will be merged in the app into a single match.

This currently applies to Main Match and Main Match Part 2 and 3 (these names are editable). All three are imported directly as Main Match, therefore it is recommended to distinguish individual days by posse number.