refactor(GraphQL): Rename objectId to id (#5985)

* refactor(GraphQL): Rename objectId to id

Renames `objectId` to `id` for the GraphQL API. Queries, mutations,
custom and generic types were updated.
Removes `RELATION_INPUT` and `POINTER_INPUT`. Now the user just need
to provide the ID of the object to link.

* fix: Column "id" not found on Postgres

* fix: Avoid deleting Parse class objectId

* fix: Undo objectId removal on mutations

* fix: Handle generic mutation id

src/GraphQL/parseGraphQLUtils.js

@@ -17,9 +17,17 @@ export const extractKeysAndInclude = selectedFields => {
   selectedFields = selectedFields.filter(
     field => !field.includes('__typename')
   );
+
+  // Handles "id" field for both current and included objects
+  selectedFields = selectedFields.map(field => {
+    if (field === 'id') return 'objectId';
+    return field.endsWith('.id')
+      ? `${field.substring(0, field.lastIndexOf('.id'))}.objectId`
+      : field;
+  });
   let keys = undefined;
   let include = undefined;
-  if (selectedFields && selectedFields.length > 0) {
+  if (selectedFields.length > 0) {
     keys = selectedFields.join(',');
     include = selectedFields
       .reduce((fields, field) => {