limited update/delete requires explicit order

* limited update/delete now works on views with explicit order
* no default order, enforce order presence
* apply row count to ensure limited mutations
* move requiring order to ApiRequest

src/PostgREST/DbStructure.hs

@@ -23,7 +23,6 @@ module PostgREST.DbStructure
   , queryDbStructure
   , accessibleTables
   , accessibleProcs
-  , findIfView
   , schemaDescription
   ) where
 
@@ -66,9 +65,6 @@ data DbStructure = DbStructure
   }
   deriving (Generic, JSON.ToJSON)
 
-findIfView :: QualifiedIdentifier -> TablesMap -> Bool
-findIfView identifier tbls = maybe False tableIsView $ M.lookup identifier tbls
-
 -- | A view foreign key or primary key dependency detected on its source table
 data ViewKeyDependency = ViewKeyDependency {
   keyDepTable :: QualifiedIdentifier