users-in-app-update: Update BulkEditController to support USERS content update

Purpose/Overview:

BulkEditController should be updated to support UserContentUpdateCollection.

Requirements/Scope:

1. Endpoint POST /bulk-edit/{jobId}/user-content-update/upload should be implemented. It should receive UserContentUpdateCollection object and return userCollection.json as a result of business logic processing. 
2. BulkEditController should call BulkEditUserContentUpdateService.
3. Both users and errors preview endpoints business logic should be updated to support corresponding operations for users.

Approach:

Update swagger-file, update BulkEditController to support UserContentUpdateCollection (updating, both updated users and errors preview flows),  implement unit tests/karate tests.

Acceptance criteria:

• Endpoint POST /bulk-edit/{jobId}/users-content-update/upload should be implemented in the BulkEditController.
• Unit tests are implemented (code coverage > 80%).

Note: ResponseEntity<Object> getPreviewUsersByJobId() -> ResponseEntity<UserCollection> getPreviewUsersByJobId()