Created|Deleted refactoring

* refactors base attributes created and deleted into UserActionLogEntry foreign keys
* refactors all related queries and process logic
* fixes binding_on into binding_date in intervention/detail/view.html
* adds basic __str__ for some models
*

compensation/admin.py

@@ -37,8 +37,7 @@ class CompensationAdmin(admin.ModelAdmin):
         "id",
         "identifier",
         "title",
-        "created_on",
-        "created_by",
+        "created",
     ]
 
 
@@ -47,8 +46,6 @@ class EcoAccountAdmin(admin.ModelAdmin):
         "id",
         "identifier",
         "title",
-        "created_on",
-        "created_by",
     ]
 
 
@@ -57,8 +54,6 @@ class PaymentAdmin(admin.ModelAdmin):
         "id",
         "amount",
         "due_on",
-        "created_by",
-        "created_on",
     ]
 
 
@@ -68,8 +63,6 @@ class EcoAccountWithdrawAdmin(admin.ModelAdmin):
         "account",
         "intervention",
         "amount",
-        "created_by",
-        "created_on",
     ]