Add introducer add command

- Create a command to add an introducer (with domains).
- Add a module for escaping regular expressions used in certifications
- Add some helper functions.

src/commands/introducer.rs

@@ -11,7 +11,7 @@ pub mod remove;
 pub async fn dispatch(cmd: IntroducerCommand, config: HuskConfigContainer) -> Result<()> {
     match cmd.subcommand {
         IntroducerSubcommand::Add(add_cmd) => {
-            add::dispatch(add_cmd, &config).await?;
+            add::dispatch(add_cmd, config).await?;
         },
         IntroducerSubcommand::Remove(rm_cmd) => {
             remove::dispatch(rm_cmd, &config).await?;