Core/Conditions

* rewritten and moved to its own class, should be easier to expand in the future
 * add missing sources and types from TrinityCore
 * implement conditions on Areatrigger and Loot containers
 * implement reverse lookups (e.g. a spell is a conditional for something else)
 * general beautification pass .. should be more legible in general

NOTE:
 * texts have been changed, so the existing translation for esES ist gone
 * selecting and describing condition targets is still wonky

includes/basetype.class.php

@@ -859,9 +859,9 @@ trait sourceHelper
     protected $sources    = [];
     protected $sourceMore = null;
 
-    public function getSources(?array &$s, ?array &$sm) : bool
+    public function getSources(?array &$s = [], ?array &$sm = []) : bool
     {
-        $s = $sm = null;
+        $s = $sm = [];
         if (empty($this->sources[$this->id]))
             return false;