(docs) Add notice for rules in Community extension

This adds a new component that can be used to mark Package Validator
rules as not yet being implemented in Package Validator, but however has
been implemented in the Chocolatey Community Validation Extension.

Author: AdmiringWorm

src/components/docs/PackageValidatorNotImplemented.mdx

@@ -0,0 +1,12 @@
+---
+
+---
+import Callout from '@choco/components/Callout.astro';
+import Iframe from '@choco/components/Iframe.astro';
+import Xref from '@components/Xref.astro';
+
+<Callout type="warning">
+    This rule has not been implemented in Package Validator, and is only available in the Chocolatey Community Validation extension.
+
+    Once it has been implemented in Package Validator, the severity or behavior may be changed in the Chocolatey Community Validation extension.
+</Callout>