Enable Hermes

[code-jenn-or]

Consider enabling hermes by default for better optimization and smaller download size.
To enable, add to the app/build.gradle:

project.ext.react = [
    entryFile: "index.js",
    enableHermes: true,  // clean and rebuild if changing
]

Also add resolution strategy to the app/build.gradle until we upgrade to 0.62

configurations.all {
     resolutionStrategy {
       force "com.facebook.soloader:soloader:0.8.0"
     }
}