Update Gradle

[sbeca]

When I build the Android version of an application I'm developing that is using react-native-image-sequence, I get the following warnings during the Gradle build stage:

> Configure project :react-native-image-sequence

WARNING: Configuration 'compile' is obsolete and has been replaced with 'implementation' and 'api'.
It will be removed at the end of 2018. For more information see: http://d.android.com/r/tools/update-dependency-configurations.html
WARNING: The specified Android SDK Build Tools version (23.0.1) is ignored, as it is below the minimum supported version (28.0.3) for Android Gradle Plugin 3.3.1.
Android SDK Build Tools 28.0.3 will be used.
To suppress this warning, remove "buildToolsVersion '23.0.1'" from your build.gradle file, as each version of the Android Gradle Plugin now has a default version of the build tools.

This PR updates Gradle and a bunch of Gradle related settings. It also adds the ability to use the root project's values for a number of Gradle build settings, which has become a standard in the React Native world.