refactor: make Query module pure

This splits off the transaction concerns into a MainTx module

It's just moving some functions inside the Query module to the MainTx module.
Some types names were also changed so they don't have the "Query" prefix, to avoid confusion.

src/PostgREST/Response.hs

@@ -34,13 +34,13 @@ import PostgREST.ApiRequest.QueryParams  (QueryParams (..))
 import PostgREST.ApiRequest.Types        (InvokeMethod (..),
                                           Mutation (..))
 import PostgREST.Config                  (AppConfig (..))
+import PostgREST.MainTx                  (DbResult (..),
+                                          ResultSet (..))
 import PostgREST.MediaType               (MediaType (..))
 import PostgREST.Plan                    (CrudPlan (..),
                                           InfoPlan (..),
                                           InspectPlan (..))
 import PostgREST.Plan.MutatePlan         (MutatePlan (..))
-import PostgREST.Query                   (QueryResult (..),
-                                          ResultSet (..))
 import PostgREST.Response.GucHeader      (GucHeader, unwrapGucHeader)
 import PostgREST.SchemaCache             (SchemaCache (..))
 import PostgREST.SchemaCache.Identifiers (QualifiedIdentifier (..),
@@ -60,7 +60,7 @@ data PgrstResponse = PgrstResponse {
 , pgrstBody    :: LBS.ByteString
 }
 
-actionResponse :: QueryResult -> ApiRequest -> (Text, Text) -> AppConfig -> SchemaCache -> Schema -> Bool -> Either Error.Error PgrstResponse
+actionResponse :: DbResult -> ApiRequest -> (Text, Text) -> AppConfig -> SchemaCache -> Schema -> Bool -> Either Error.Error PgrstResponse
 
 actionResponse (DbCrudResult WrappedReadPlan{pMedia, wrHdrsOnly=headersOnly, crudQi=identifier} RSStandard{..}) ctxApiRequest@ApiRequest{iPreferences=Preferences{..},..} _ _ _ _ _ = do
   let