Validate application config on startup

### Description

Applications with missing or invalid configurations should fail fast and give good exceptions to ease the effort for developers to track down the source of the problem.

Ideally this startup checks should make it easy to extend to make it easier to break down and deliver small and isolated checks that are easy to evolve and extend as the product changes. This should also make it easy for developers to create custom validations they would like to run at startup.

Some checks could also be executed at compile time to make the "app" fail even faster

### Additional Information

_No response_

Start by locating the application startup and configuration entry points in the library, since the issue names no specific files or tests. Define the validation scope, extension point for custom checks, exception expectations, and which checks could run at compile time; the work is done when invalid configuration fails fast with useful diagnostics.

Written by the indexing model from the issue text.