[Feature] App/Route specific Middleware/Listeners

[gouthamve]

I see that we are having Middleware across the whole API, but not over the invoking endpoints. I think it would be great to have App/Route specific Middleware for them.

One use-case would be that some apps/routes might want authentication (Vault based, for example) to be invoked. This would be something similar to IAM roles for invoking functions.

Extreme example, but I think the use-cases are there.