Document for mocked cpu app within quickstart page

[Colstuwjx]

Hi team, I've found that we've filed a document for illustrating how to do the local development, see repo folder, however, there are two issues:

1. it's not clear for end users to check out the document since the document page didn't have the full guide, instead, we need to check the repo folder for more details, which is really painful;
2. in order to improve the user experience for the end users, could we update the quickstart page to add the cpu type vllm model example so that it's more easier to try out aibrix features.

Thanks.