added Inventory UI

added logic to inventory
 * it is very possible to be reworked in the near future
 * With
   - ScriptableItem
   - an own Inventory class maybe
   - if necessary no Dictionary anymore

ProjectSettings/InputManager.asset

@@ -485,3 +485,20 @@ InputManager:
     type: 2
     axis: 5
     joyNum: 0
+  - serializedVersion: 3
+    m_Name: Inventory
+    descriptiveName: 
+    descriptiveNegativeName: 
+    negativeButton: 
+    positiveButton: e
+    altNegativeButton: 
+    altPositiveButton: i
+    gravity: 1000
+    dead: 0.001
+    sensitivity: 1000
+    snap: 0
+    invert: 0
+    type: 0
+    axis: 0
+    joyNum: 0
+  m_UsePhysicalKeys: 0