Article: Mechanics of Contributing

We should produce a written article based on the **Mechanics of Contributing** section of the [_Contributor_ outline](https://github.com/InnerSourceCommons/InnerSourceLearningPath/blob/master/contributor/outline.md).

The article should teach the same points as the [Mechanics of Contributing Video](https://github.com/InnerSourceCommons/InnerSourceLearningPath/issues/73).