"CreateEmptyBuilder" but a little more robust

## Background and Motivation

I have a lot of microservices running on .net and one thing is very certain: they use a lot more memory than CPU... their are host on AKS and this is the big picture of my MEMORY OPTIMIZED pools:

One could argue that yeah, Azure could launch a VM set for 1cpu 8gb ram, but meanwhile, if I want to drive costs down on the hosting, I need to save memory...

Reading that "CreateEmptyBuilder" launches a app at 8.5MB brings tears to my eyes, because YESSSSS my teams will be able to run really slim microservices but also SHIIIIIIIIIT they will screw-up so bad counting on things that are usually there but won't be, like model mapping...

## Proposed API

I would like to propose the "CreateMinimalApiBuilder", with just enough to serve the API part of the "WeatherForecast" default template. Nothing else.

A alternative could be template where the builder is explicit and we could just delete/comment things out