Add Typography Props Mixin

When a component is primarily text ( i.e title, subtitle components ) it should allow typography classes to be passed as a boolean.

Example:

This would add the `h5` class.
```js

```

Since this would apply to several components a mixin can be created to avoid repetition.

Things to include:

* Headers i.e `h1`
* Colors i.e `text-gray`
* Positioning i.e `text-center`

https://picturepan2.github.io/spectre/elements.html#typography

https://picturepan2.github.io/spectre/utilities.html