Revert "Add extended Form base class which triggers events on important method calls"

This reverts commit ec4c151361282e1c15acd5c76b0bd578521b32ab.
Implement ExtendedValidationGroupForm which overrides Zend\Form\Form's default handling of validation groups
Complete implementation of frontend editing of competition matches for *_admin roles
Update Competition, Team and Union forms to use ExtendedValidationGroupForm