chore(github): remove /examples from contribution guidelines, remove examples issue template (#77050)

## Why?

Start the prep-work for removing/moving [Next.js examples](https://github.com/vercel/next.js/tree/canary/examples).

Today, a lot of these examples already have their own dedicated location in their respective GitHub orgs.

These examples are also now present in other locations.

- https://github.com/nextjs
- https://v0.dev/chat/community
- https://vercel.com/templates/next.js

Author: samcx

.github/ISSUE_TEMPLATE/2.example_bug_report.yml

@@ -16,13 +16,6 @@
 
 - [Adding Documentation](./contributing/docs/adding-documentation.md)
 
-## Examples
-
-To contribute to [our examples](./examples), please see
-
-- [Adding Examples](./contributing/examples/adding-examples.md)
-- [Run Example Apps](./contributing/examples/run-example-apps.md)
-
 ## Core
 
 - [Developing](./contributing/core/developing.md)