android build: Cut never-used Buck config.

This all comes from the template React Native app.

We don't use Buck and never have; so the only thing this BUCK file
and other stuff can do is cause confusion.  Take it out.

.flowconfig

@@ -2,9 +2,6 @@
 ; We fork some components by platform
 .*/*[.]android.js
 
-; Ignore "BUCK" generated dirs
-<PROJECT_ROOT>/\.buckd/
-
 ; Ignore unexpected extra "@providesModule"
 .*/node_modules/.*/node_modules/fbjs/.*
 

.gitignore

@@ -36,12 +36,6 @@ local.properties
 node_modules/
 npm-debug.log
 
-# BUCK
-buck-out/
-\.buckd/
-android/app/libs
-android/keystores/debug.keystore
-
 ### ^
 ### The portion of this file above this line comes from RN upstream's
 ### template.  We leave that part unchanged as much as we can, to help

android/app/build.gradle

@@ -224,10 +224,3 @@ tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
         jvmTarget = "1.8"
     }
 }
-
-// Run this once to be able to run the application with BUCK
-// puts all compile dependencies into folder libs for BUCK to use
-task copyDownloadableDepsToLibs(type: Copy) {
-  from configurations.compile
-  into 'libs'
-}