Miscellaneous additions/refactoring

* Create "BaseSimutronicsMovementScript" and related test stub
* Purge "BaseDragonrealmsBridge" and move some logic into
  "BaseSimutronicsBridge"
* Update "{Dragonrealms,Gemstone}PrimeBridge" to inherit directly from
  "BaseSimutronicsBridge"
* Rework "GreaterBurrowOrcScript"
* Create "GreaterBurrowOrcReturnScript" and related test stub
* Create "SurgeScript" and related test stub