[OE-4109] catch email failure
[OE-4109] removed flash message
[OE-4109] updated config urgent booking email format
[OE-4109] moved booking config from core
Remove obsolete LoggableBehavior.
Migration method to version existing table.
Strip foreign keys from version tables and don't use soft deletion everywhere.
Lookup table behaviour.
Pull data from a lookup table in BaseEventTypeCActiveForm::dropDownList().
Remove SoftDelete and apply LookupTable behaviour where appropriate.