Add Prebuilt Rendering Classes

[Foxbud]

As it stands, users must create their own renderer class by extending BaseRenderer. While the library does provide several mixins for common use-cases, they still require a custom renderer subclass.

This issue proposes the addition of the following ready-to-use classes to help the library better follow Python's "batteries included" philosophy:

• SimpleRenderer - extends TagDictMixin and BaseRenderer
• TrimmedRenderer - extends TrimMixin, TagDictMixin and BaseRenderer