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/cli/cli_args.rs

@@ -25,7 +25,7 @@ pub struct CliArgs {
 pub enum HuskSubcommands {
     Daemon(DaemonCommand),
     Introducer(IntroducerCommand),
-    Local(LocalCommand),
+    Locals(LocalsCommand),
 }
 
 // Daemon subcommands
@@ -134,23 +134,23 @@ pub struct IntroducerRemoveCommand {
     disable_colored_help = true,
     disable_version_flag = true,
 )]
-pub struct LocalCommand {
+pub struct LocalsCommand {
     #[clap(subcommand)]
-    pub subcommand: LocalSubcommand,
+    pub subcommand: LocalsSubcommand,
 }
 #[derive(Debug, Subcommand)]
-pub enum LocalSubcommand {
-    Add(LocalAddCommand),
-    Remove(LocalRemoveCommand),
+pub enum LocalsSubcommand {
+    Add(LocalsAddCommand),
+    Remove(LocalsRemoveCommand),
     List
 }
 
 #[derive(Parser, Debug)]
 #[clap(
-    name = "local_add",
+    name = "locals_add",
     about = "Add an authenticated certificate.",
 )]
-pub struct LocalAddCommand {
+pub struct LocalsAddCommand {
     #[clap(
         long = "cert",
         help = "Certificate to add."
@@ -160,10 +160,10 @@ pub struct LocalAddCommand {
 
 #[derive(Parser, Debug)]
 #[clap(
-    name = "local_remove",
+    name = "locals_remove",
     about = "Certificate to remove.",
 )]
-pub struct LocalRemoveCommand {
+pub struct LocalsRemoveCommand {
     #[clap(
         long = "cert",
         help = "Certificate to removed."