Parent Key Value

[JesseAbram]

In #918 the network creates a parent key and currently uses the 0x00 address

However in ed25519 and sr25519 that is an insecure account, actions on the address are blocked anyways, however there could be potential secondary effects we are not aware of (probably not but still why tempt fate)

The shard can sit under any key value in the kvdb and having it known actually helps, changing it to "NETWORK_PARENT_KEY" seems to make sense