refactor(idecap-cms-widget-richtext): implementation of platejs.org from @demshy

 - Applied implementation from https://github.com/poslovnimediji/decap-cms/tree/widget-richtext

 - Based on PR decaporg#7162

Author: RaphaelBossek

.eslintrc.js

@@ -64,6 +64,7 @@ module.exports = {
       node: {
         extensions: ['.js', '.jsx', '.ts', '.tsx'],
       },
+      exports: {},
     },
     'import/core-modules': [...packages, 'decap-cms-app/dist/esm'],
   },

dev-test/config.yml

@@ -49,7 +49,9 @@ collections: # A list of collections the CMS should be able to edit
         required: false
         tagname: ''
 
-      - { label: 'Body', name: 'body', widget: 'markdown', hint: 'Main content goes here.' }
+      - { label: 'Body', name: 'body', widget: 'richtext', hint: 'Main content goes here.' }
+      - { label: 'Body', name: 'bodyold', widget: 'markdown', hint: 'Main content goes here.' }
+      - { label: 'Body', name: 'bodyold2', widget: 'markdown', hint: 'Main content goes here 2.' }
 
   - name: 'restaurants' # Used in routes, ie.: /admin/collections/:slug/edit
     label: 'Restaurants' # Used in the UI