exoflex: babel-plugin

[oshimayoan]

Is your feature request related to a problem? Please describe.
Not every component in exoflex will be used on one project but the bundler will keep including those components so the bundle size will become bigger than it should.

Describe the solution you'd like
Create a babel-plugin to exclude components that aren't imported by the project. This solution is similar to what RNP has.

Describe alternatives you've considered
None at the moment.