Add callouts support

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

packages/remark-callouts/tsconfig.json

@@ -0,0 +1,14 @@
+{
+    "compilerOptions": {
+        "target": "es2020",
+        "module": "esnext",
+        "strict": true,
+        "esModuleInterop": true,
+        "moduleResolution": "node",
+        "skipLibCheck": true,
+        "noImplicitAny": true,
+        "allowJs": true,
+        "noEmit": true,
+        "resolveJsonModule": true
+    }
+}