✨ Add MQTT Trigger-Node (#885)

* Improvements to MQTT-node

* ⚡ Small improvements

done

* ⚡ Improvements

Co-authored-by: LEE SANG JUN <blackr8t@gmail.com>

packages/nodes-base/credentials/Mqtt.credentials.ts

@@ -0,0 +1,59 @@
+import {
+	ICredentialType,
+	NodePropertyTypes,
+} from 'n8n-workflow';
+
+
+export class Mqtt implements ICredentialType {
+	name = 'mqtt';
+	displayName = 'MQTT';
+	properties = [
+		// The credentials to get from user and save encrypted.
+		// Properties can be defined exactly in the same way
+		// as node properties.
+		{
+			displayName: 'Protocol',
+			name: 'protocol',
+      type: 'options' as NodePropertyTypes,
+      options: [
+				{
+					name: 'mqtt',
+					value: 'mqtt',
+				},
+				{
+					name: 'ws',
+					value: 'ws',
+				},
+			],
+			default: 'mqtt',
+		},
+		{
+			displayName: 'Host',
+			name: 'host',
+			type: 'string' as NodePropertyTypes,
+			default: '',
+		},
+		{
+			displayName: 'Port',
+			name: 'port',
+			type: 'number' as NodePropertyTypes,
+			default: 1883,
+		},
+		{
+			displayName: 'Username',
+			name: 'username',
+			type: 'string' as NodePropertyTypes,
+			default: '',
+		},
+		{
+			displayName: 'Password',
+			name: 'password',
+			type: 'string' as NodePropertyTypes,
+			typeOptions: {
+				password: true,
+			},
+			default: '',
+		},
+	];
+}
+