Add component-no-value exception

[KGOH]

Implements #37

[darkleaf]

You don’t need the stack here. You can identIfy an invalid component just by its key

[KGOH]

While just a key is enough to identify the component, it may not be enough in a case when a component returns nil, but I didn't expect this component to be executed at all. In such case it may be obvious why the component returns nil, but it would be not clear at all why this component was used at all in a such configuration

Though, we can omit the stack and wait when we stumble upon a such case where a stack would be helpful to see

[darkleaf]

There seem to be two issues. The first is a notification about invalid component.
The second is about adding extra info such a stack of components.

You can solve the second with the following pattern:

(try
  (...)
  (catch RuntimeException ex
    (throw (ex-info "..." {:stack stack} ex))))

[KGOH]

Good idea!
@slaughtlaught ^^^