[REF] Fix Event location to create it's locations directly rather than via shared...

[REF] Fix Event location to create it's locations directly rather than via shared methods

This form does extra work in order to call  CRM_Core_BAO_Block::create and CRM_Core_BAO_Address::create - but they have
extra handling that only exists for this code place. So, we are making 2 functions more complex in order to inter-relate them.

This simplifies the CRM_Event_Form_ManageEvent_Location and I will do follow on cleanup once merged. Note I previously
added tests to CRM_Event_Form_ManageEvent_LocationTest specifically to cover this (in a recent previous refactor