subcommand and /abort fixes

- use AbortController in /abort instead of execption
- allow quiet abort
- allow loud abort
- allow abort reason
- abort when aborted in subcommand
- break out of loops when aborted inside
- fix parsing of subcommands with multiple commands

public/scripts/slash-commands/SlashCommandClosureResult.js

@@ -2,6 +2,7 @@ export class SlashCommandClosureResult {
     /**@type {boolean}*/ interrupt = false;
     /**@type {string}*/ pipe;
     /**@type {boolean}*/ isAborted = false;
+    /**@type {boolean}*/ isQuietlyAborted = false;
     /**@type {string}*/ abortReason;
     /**@type {boolean}*/ isError = false;
     /**@type {string}*/ errorMessage;