content: Remove offline plugins

plugins.json

@@ -461,16 +461,6 @@
     "homepage": "https://github.com/awkward/Alembic",
     "lastUpdated": "2018-05-22 13:51:22 UTC"
   },
-  {
-    "description": "Overlay transforms your Sketch symbols into clean and reusable code in ReactJS, Vue.js and Vanilla HTML.",
-    "name": "Overlay",
-    "title": "Overlay",
-    "owner": "overlay",
-    "author": "Overlay",
-    "homepage": "https://overlay-tech.com?ref=sketch-plugin",
-    "lastUpdated": "2023-01-01 19:30:00 UTC",
-    "appcast": "https://overlay-plugin.s3-eu-west-1.amazonaws.com/public/sketch/.appcast.xml"
-  },
   {
     "description": "Add single borders with advanced controls.",
     "name": "single-border",
@@ -1060,15 +1050,6 @@
     "title": "Color Copier",
     "lastUpdated": "2018-05-26 15:43:41 UTC"
   },
-  {
-    "description": "Sketch Plugin to make documenting design easier.",
-    "owner": "marcosvidal",
-    "author": "Marcos Vidal",
-    "title": "Sketch Notebook",
-    "name": "Sketch-Notebook",
-    "homepage": "http://marcosvid.al/sketch-notebook",
-    "lastUpdated": "2020-07-08 18:06:41 UTC"
-  },
   {
     "description": "Modulizer plug-in for Sketch.app allows you easy control paddings for buttons, modules and areas. If your module has background your can set fixed paddings and easy restore it for any content changes.",
     "owner": "Falkeyn",