Method SoftDelete_PurgeTrash()

SQL to purge (physically delete) objects from trash container.
Deletes in batches, removes trash container when empty.
Params: $1=trashId, $2=batchSize
Returns: deleted_count, remaining_count
PostgreSQL: SELECT * FROM purge_trash($1, $2)
MSSQL: EXEC sp_purge_trash , (with OUTPUT params)

string SoftDelete_PurgeTrash()