use OnActivating instead of OnActivated

- ensures properties are loaded before the item is passed into a ctor
add nullable dynamic param to ISqlTable.DeleteAll
update SubscriberMetadataFactory to not insert default values when empty

- and remove unused field
add subscribers-ls cmd to show latest subscribers
add subscribers-reset cmd to remove current hub and subscribers
remove unused using
move commands to Druq.Hub so they can be used in event processor
move version command to be used by event processor
Merge pull request #63 from daptiv/62903-override-subscriber-attr

62903 override subscriber attr