revert c4206b7d341c9f28285efa0582ab0271ddfeaa49

revert 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/themes.js

@@ -1,25 +0,0 @@
-const GCGThemeDark = {
-  name: "GCG.Dark",
-  extends: "dark",
-  primary: {
-    main: "#ffbc3b",
-    contrastColor: "#4b4b4b",
-  },
-  background: {
-    main: "#1a1a37",
-    dark: "#13132d",
-  },
-};
-
-const GCGThemeLight = {
-  name: "GCG.Light",
-  extends: "light",
-  primary: {
-    main: "#1a1a37",
-  },
-  background: {
-    dark: "#f1f3f5",
-  },
-};
-
-export { GCGThemeDark, GCGThemeLight };