Add container aware trait

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | will create one if merged

This trait can be used inside a class to make it container aware. As it is not always possible to extend the abstract ContainerAware class, the code for creating a container aware class is usually copied over and over (most of the time unchanged), resulting in a lot of redundant code in your project. As my projects are PHP 5.4 based nowadays, I would like to be able to use a trait in these scenarios to improve my workflow.