[BUGFIX] Register SuggestFormFactory as service (#33)

The `SuggestFormFactory` is renderd via a ViewHelper within Fluid, where DI is not available. Therefore, the factory class needs to be registered explicitly.

Configuration/Services.yaml

@@ -10,5 +10,8 @@ services:
   Evoweb\Sessionplaner\Controller\AjaxController:
     public: true
 
+  Evoweb\Sessionplaner\Domain\Factory\SuggestFormFactory:
+    public: true
+
   Evoweb\Sessionplaner\Domain\Finisher\SuggestFormFinisher:
     public: true