feat(writekit): rename @robonen/editor to @robonen/writekit

Rename the rich-text editor package and all Editor* exports to Writekit*;
remove the old vue/editor tree.

vue/writekit/playground/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "extends": "@robonen/tsconfig/tsconfig.vue.json",
+  "compilerOptions": {
+    "baseUrl": ".",
+    "paths": {
+      "@writekit": ["../src/index.ts"],
+      "@writekit/*": ["../src/*"]
+    }
+  },
+  "include": ["src", "vite.config.ts"]
+}