Added IndexStorageSize and TransactionalStorageSize to new Responder database/storage/sizes

To get a better view into actual storage, in case of planning out
hardware infrastructure, I added the ability to see IndexStorageSize and
TransactionalStorageSize separate, in addition to the TotalDatabaseSize.

Oren: Not sure if you will allow this pull request, however I think it could be useful for someone when trying to plan out hardware infrastructure when splitting indexes and databases to separate drives. It often seems that index storage takes far less space than the transactional storage.