Allow setting custom options via a JSON file

[zugaldia]

This PR introduces a few changes:

• Custom options can now be set via a JSON file, there's no need to hardcode values anymore.
• There's a new shared class to handle storage locations and availability.
• Camera component now uses the new storage manager.
• A new options package takes care of loading the JSON file async.
• Main Activity renamed for consistency, previous Constant file is now removed.

Still a work in progress, have to test it on a device.

cc: @hsalameh