Make location provider library dependency optional

[zugaldia]

Building upon the flexibility brought by mapbox/mapbox-java#269 and #8668, we'd like to make LOST a provided (optional) dependency. This enables developers to rely on core Android location services or to use Google Play Services without having to bundle unused dependencies.

This change brings additional benefits:

1. It reduces the default dependencies (size and method count) bundled with the SDK
2. Developers can set their own library versions and work around any issues present on those libraries.

The proposed approach is:

• Bundle default LocationEngine implementations for Android core, LOST, and Google Play Services backends
• Add LOST and Google Play Services to build.gradle as optional dependencies
• At runtime, detect whether LOST or Google Play Services are available
• Let the developer set a priority preference for location provider backend

@mapbox/android Any thoughts?