Break up library into smaller components for lower binary sizes.

[codingiswhyicry]

Something that I'm thinking about as we prepare for Verena to hit the decks: we should break the aureus_lib.dart file into way smaller chunks so someone can be more picky (or broad) about what they import. This would also help us to reduce the overall binary sizes of shipped resources.

We can just break them into the subcategories they are, and then re-import into aureus_lib.dart: e.g: Safety, Buttons, etc.