Add more Container constructors

[Chingling152]

Summary

Add default constructors to Container<T>, StackContainer<T>, and LazyStackContainer<T> that internally instantiate their respective Slot implementations, removing the current requirement to use Dependency Injection for basic usage.

Motivation

At the moment, these container types can only be instantiated by providing their Slot dependencies via DI.
Requiring the Creation of the Slots in all cases raises the entry barrier of the API and makes some simple scenarios more complex than needed.

Proposed Solution

Introduce additional default constructors for Container<T>, StackContainer<T>, and LazyStackContainer<T> that might work as Factory methods.