Documentation Improvements

[julianfalcionelli]

We are adding many functionalities to the project, so it would be good to go by adding references to each of these functionalities in the Readme or in the Wiki, making references to the code/classes and useful documentation. It could be something like:

List of functionalities in this project:

• Push Notifications: Firebase Push Notifications was integrated.
• REST API: For this we use Retrofit. The core class is RetrofitManager, which contains several ways to configure our Http instances, such as cache configuration, logs, and more.
• MotionLayout
• Camera
• etc...

We can also talk a bit about the architecture and some design patterns that we use such as Dependency Injection, Dependency Inversion, etc.

We can do this together, each one can focus on the functionalities in which they mainly work.

[IvanToplak]

I've updated documentation in readme file.
It's not a final list of functionalities that we implemented, but I did cover most of it.