Add locals add and remove subcommands

- `locals add` adds a local (unintroduced) certificate for encryption.
- `locals remove` removes/deacivates a local certificate.
- Overall cleanup

src/commands/introducer/add.rs

@@ -31,14 +31,14 @@ pub async fn dispatch(cmd: IntroducerAddCommand, config: HuskConfigContainer) ->
         if matches!(vc.revocation_status(), RevocationStatus::Revoked(_)) {
             return Err(CommandError::CertRevoked(vc.fingerprint()).into());
         }
-        if !crypto::has_certification_capability(&vc) {
+        if !crypto::can_certify(&vc) {
             return Err(CommandError::CertNotUsable(vc.fingerprint()).into());
         }
 
         Introducer::create(&context, &vc, cmd.domains)?;
     } else if let Some(cert) = cmd.cert {
         let fpr = Fingerprint::from_hex(cert.as_str())?;
-        let certs = cert_store.lookup_by_cert(&KeyHandle::try_from(&fpr)?)
+        let certs = cert_store.lookup_by_cert(&KeyHandle::from(&fpr))
             .map_err(|_| CommandError::CertNotFound(fpr.clone()))?;
 
         let certs: Vec<ValidCert> = certs.iter()
@@ -48,7 +48,7 @@ pub async fn dispatch(cmd: IntroducerAddCommand, config: HuskConfigContainer) ->
             .collect();
 
         if let Some(cert) = certs.first() {
-            Introducer::create(&context, &cert, cmd.domains)?;
+            Introducer::create(&context, cert, cmd.domains)?;
         } else {
             return Err(CommandError::CertNotUsable(fpr).into());
         }