Improve the Backend for Mass Record Deletion

[Bonapara]

Current Behavior

pg_graphql constraints restrict deletion to a maximum of 30 records per operation.

Desired Behavior

Implement a loop on the delete request to delete more records in a single operation.

[pacyL2K19]

I can work on this @Bonapara cc: @FelixMalfait

[FelixMalfait]

Thanks @pacyL2K19 I think the master issue which includes this was taken by @gitstart-twenty