Add callouts support

Adds a colour palette
Adds homemade remark-callouts package
Adds tabler icons dependency

packages/remark-callouts/rollup.config.js

@@ -0,0 +1,20 @@
+// rollup.config.js
+import typescript from '@rollup/plugin-typescript';
+import { dts } from "rollup-plugin-dts";
+import pkg from './package.json' with { type: "json" };
+
+export default [
+    {
+        input: 'src/index.ts',
+        output: [
+            { file: pkg.exports.require, format: 'cjs' },
+            { file: pkg.exports.import, format: 'es' }
+        ],
+        plugins: [typescript()]
+    },
+    {
+        input: 'src/index.ts',
+        output: [{ file: pkg.exports.types, format: 'es' }],
+        plugins: [dts()],
+    }
+];