Split shared component between MainThread and CoreAnimation.

[chuynadamas]

In this PR, I'm making changes to the Lottie library that will help us to optimize the performance of our animations. Since Lottie 4.1.1, the CoreAnimation renderer has been set as default which means that in the future all the animations will be rendered using it instead of the MainThread renderer.

To make the future migration an easy process, I'm separating the shared components in a dedicated folder named "SharedComponents" that currently are used for both renderers. This will also create a clear boundary between both implementations and decouple them.

As an additional benefit, we are also separating both renderers logic into independent modules that will create the flexibility to import one or both if needed. This will create a binary size benefit, making the Lottie library more lightweight and efficient.

I've created a fork with this change in place, just moving the files from one place to another, that you can check here:
branch