Use more intuitive module structure

[WillieCubed]

The current modules (app and base in particular) have classes scattered around in a generally unorganized mess. We should create a few new feature modules to separate components that are used for the different components like only instant apps or Android Things, the app, and/or a multiple of the modules listed. While the base module has a logical package structure, many classes in the app module should not be located at the root package.

Specifically, the goals are:

• Clean up the base module's classes and package structure
• Create a necessary amount of modules based on big features
• Revise dependency structure for all the modules

[WillieCubed]

While we're at it, we need to clean up all the dead code and deprecated components throughout the project.