* Rename (keypair util is not a thing)
* Add method to generate_unique_signers
* Cli: refactor signer handling and remote-wallet init
* Fixup unit tests
* Fixup intergation tests
* Update keypair path print statement
* Remove &None
* Use deterministic key in test
* Retain storage-account as index
* Make signer index-handling less brittle
* Cache pubkey on RemoteKeypair::new
* Make signer_of consistent + return pubkey
* Remove &matches double references
* Nonce authorities need special handling
* Add fallible methods to KeypairUtil
* Add RemoteKeypair struct and impl KeypairUtil
* Implement RemoteKeypair in keygen; also add parse_keypair_path for cleanup