add settings for master and minion to sign the public / verify pubkey signature
add settings for master and minion to sign the public / verify pubkey signature

Add a setting for the master to generate a new signing key-pair for signing purposes
and use the key-pair to sign the masters public key that is send to authenticated
minions.

Add a setting for the minion to verify the signature of a public key received from
the master. Requires to have the signing key-pair from the master on the minion.

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt