Remove common_currency model entirely

- A lot of views / pages / etc needed to be updated too
- Now uses django-money fields entirely
- Create a manual rate exchange backend (needs more work!)

InvenTree/part/serializers.py

@@ -84,13 +84,9 @@ class PartSalePriceSerializer(InvenTreeModelSerializer):
     Serializer for sale prices for Part model.
     """
 
-    symbol = serializers.CharField(read_only=True)
-
-    suffix = serializers.CharField(read_only=True)
-
     quantity = serializers.FloatField()
 
-    cost = serializers.FloatField()
+    price = serializers.CharField()
 
     class Meta:
         model = PartSellPriceBreak
@@ -98,10 +94,7 @@ class PartSalePriceSerializer(InvenTreeModelSerializer):
             'pk',
             'part',
             'quantity',
-            'cost',
-            'currency',
-            'symbol',
-            'suffix',
+            'price',
         ]