v0.25.0

Changelog:

• x/txfee extension created and integrated in cmd/bnsd. Txfee add
  additional fee depending on the transaction binary size.

Breaking changes

• bnsd/x/preregistration extension created and integrated into bnsd. It
  allows for preregistering account domains that later will be migrated into
  the account implementation using a data migration.
• x/escrow: CreateMsg.Source is no longer optional and is now required.
• x/sigs: BumpSequenceMsg.User is now required and cannot be empty.