* Add keypair_util_from_path helper
* Cli: impl config.keypair as a trait object
* SDK: Add Debug and PartialEq for dyn Signer
* ClapUtils: Arg parsing from pubkey+signers to Presigner
* Impl Signers for &dyn Signer collections
* CLI: Add helper for getting signers from args
* CLI: Replace SigningAuthority with Signer trait-objs
* CLI: Drop disused signers command field
* CLI: Drop redundant tests
* Add clap validator that handles all current signer types
* clap_utils: Factor Presigner resolution to helper
* SDK: `From` for boxing Signer implementors to trait objects
* SDK: Derive `Clone` for `Presigner`
* Remove panic
* Cli: dedup signers in transfer for remote-wallet ergonomics
* Update docs vis-a-vis ASK changes
* Cli: update transaction types to use new dynamic-signer methods
* CLI: Fix tests No. 1
what to do about write_keypair outstanding
* Work around `CliConfig`'s signer not necessarily being a `Keypair`
* CLI: Fix tests No. 2
* Remove unused arg
* Remove unused methods
* Move offline arg constants upstream
* Make cli signing fallible
Co-authored-by: Trent Nelson <trent.a.b.nelson@gmail.com>
* Add fallible methods to KeypairUtil
* Add RemoteKeypair struct and impl KeypairUtil
* Implement RemoteKeypair in keygen; also add parse_keypair_path for cleanup
* Fixup sign_transaction; pass derivation_path by reference
* Pass total message length as BE u16
* Remove live integration tests (to ledger-app-solana)
