Modernize Android build system, bump dependencies

Summary:
- Build against Android SDK 26
- Upgrade to Gradle 4
- Upgrade to Android Plugin 3.0, adjust dependency management accordingly
- Upgrade Maven deployment plugin

Reviewed By: emilsjolander

Differential Revision: D6272007

fbshipit-source-id: b198b4c8e1a94e2ee031ad26193fdfdf5b52adf1

lib/fb/build.gradle

@@ -26,8 +26,8 @@ android {
     }
 
     dependencies {
-        compile 'com.facebook.soloader:soloader:0.2.0'
-        compile 'com.google.code.findbugs:jsr305:3.0.1'
-        compile project(':yoga:proguard-annotations')
+        implementation 'com.facebook.soloader:soloader:0.2.0'
+        compileOnly 'com.google.code.findbugs:jsr305:3.0.1'
+        compileOnly project(':yoga:proguard-annotations')
     }
 }