Add MJML extension to recommended vscode workspace extensions

Author: tobiase

Diff for: .gitignore

@@ -1,4 +1,5 @@
-.vscode
+.vscode/*
+!.vscode/extensions.json
 node_modules/
 /test-results/
 /playwright-report/

Diff for: .vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+    "recommendations": [
+        "attilabuti.vscode-mjml"
+    ]
+}