Add support for SASL EXTERNAL

Can be useful when the server is using e.g. a cookie for
authentication purposes.

components/app.js

@@ -124,6 +124,7 @@ export default class App extends Component {
 			realname: null,
 			nick: null,
 			saslPlain: null,
+			saslExternal: false,
 			autoconnect: false,
 			autojoin: [],
 		},
@@ -207,6 +208,9 @@ export default class App extends Component {
 			if (typeof config.server.autoconnect === "boolean") {
 				connectParams.autoconnect = config.server.autoconnect;
 			}
+			if (config.server.auth === "external") {
+				connectParams.saslExternal = true;
+			}
 		}
 
 		let autoconnect = store.autoconnect.load();

components/connect-form.js

@@ -61,6 +61,8 @@ export default class ConnectForm extends Component {
 				username: params.username || params.nick,
 				password: this.state.password,
 			};
+		} else if (this.props.auth === "external") {
+			params.saslExternal = true;
 		}
 
 		this.state.autojoin.split(",").forEach(function(ch) {
@@ -112,7 +114,7 @@ export default class ConnectForm extends Component {
 		}
 
 		let auth = null;
-		if (this.props.auth !== "disabled") {
+		if (this.props.auth !== "disabled" && this.props.auth !== "external") {
 			auth = html`
 				<label>
 					Password:<br/>