[native] Scaffold an umbrella expo-module

Summary:
This is a first step of ENG-3871.
Created an empty expo-module directory structure and connected it to the application. In the next diffs, I'll be moving existing expo-modules
into this umbrella package.

Deliberately I put this directory inside native/expo-modules as this is the default way expected by expo-modules-autolinking. Also this approach gives us flexibility to still add new expo modules using the traditional way, if they are too large or for some reason are incompatible with this umbrella module configuration.

Don't have idea for good naming for this, though. Suggestions are welcome.

Test Plan: Cleaninstall, app builds, CI checks. Moved expo-modules will be tested in their own diffs.

Reviewers: ashoat, tomek, atul, marcin

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D7956