Idea: extensions code snippets

[ia3andy]

Description

We currently have codestarts to generate starter code for extensions.

It would be nice to also have snippets of code for extensions. This way we could:

• see/list/copy-paste snippets of code from the Quarkus tooling (and code.quarkus.io) for a given extension
• see/list/copy-paste the snippets of code for the current app from the CLI/Dev-ui
• have an integrated experience with Quarkus IDEs plugin to directly select/apply them in the code

Implementation ideas

They could be defined as qute templates with Stubbing content, and defined alongside codestarts.