CLI: collect and deduplicate signers (#8398)

* 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

sdk/src/signature.rs

@@ -183,8 +183,8 @@ impl<T> From<T> for Box<dyn Signer>
 where
     T: Signer + 'static,
 {
-    fn from(keypair_util: T) -> Self {
-        Box::new(keypair_util)
+    fn from(signer: T) -> Self {
+        Box::new(signer)
     }
 }