Add subcommand to list local certificates

- Add `husk locals list` to list all certificates which would be used by
  husk, but are not introduced by another certificate. These
  certificates are added 'locally'.
- Refcator the code so that `local` -> `locals`.

src/commands.rs

@@ -8,7 +8,7 @@ use crate::config::HuskConfigContainer;
 
 pub mod daemon;
 pub mod introducer;
-pub mod local;
+pub mod locals;
 
 #[derive(thiserror::Error, Debug)]
 pub enum CommandError {
@@ -31,8 +31,8 @@ pub async fn dispatch(cli: CliArgs, config: HuskConfigContainer) -> Result<()> {
         HuskSubcommands::Introducer(subcmd) => {
             commands::introducer::dispatch(subcmd, config).await?;
         },
-        HuskSubcommands::Local(subcmd) => {
-            commands::local::dispatch(subcmd, config).await?;
+        HuskSubcommands::Locals(subcmd) => {
+            commands::locals::dispatch(subcmd, config).await?;
         },
     }