Problem: web wallets do not allow signing raw messages. Instead,
they require binary payloads in a specific format.

Solution: support Micheline-style signatures, i.e. signatures
supported by wallets like Beacon.

Users can now use Micheline or raw signatures by specifying
the `signature.signingType` field to "micheline" or "raw".
By default, "raw" is assumed.

Co-authored-by: Mike Hukiewitz <[email protected]>

We now provide a CLI tool that integrates all the operations
commonly performed by node operators. Currently, this CLI
allows to:

* generate private keys for the node, replacing a functionality
  that was implemented in the CCN main app directly.
* run migrations, replacing the config updater script.