Static CMS v4 (#246)

- Static CMS v4
- switch from jsdelivr to unpkg due to performance issues
- custom themes
- preset view_group

Reviewed-on: #246

static/admin/config/schulchronik.js

@@ -7,6 +7,7 @@ import {
   StatsCollection,
   SuperhaufenCollection,
 } from "./collections/index.js";
+import { GCGThemeDark, GCGThemeLight } from "./themes.js";
 
 const config = {
   backend: {
@@ -38,6 +39,13 @@ const config = {
     clean_accents: true,
     sanitize_replacement: "-",
   },
+  theme: {
+    include_built_in_themes: false,
+    themes: [
+      GCGThemeDark,
+      GCGThemeLight
+    ]    
+  },
   collections: [
     ChronikjahreCollection,
     SuperhaufenCollection,