Cleanup Buck usages from New App Template (#34881)

Summary:
I'm cleaning up the Buck setup in the New App template. It hasn't been touched since 2018 and is currently not working, but will end up being propagated in user space.
This is also affecting the Gradle setup as there is a need to have an extra task just for Buck.

I doubt anyone is using this at this stage. We can get back to it or have a dedicated guide for users that are willing to use it.

## Changelog

[Android] [Remove] - Cleanup Buck usages from New App Template

Pull Request resolved: #34881

Test Plan: Testing was missing on this API so there is nothing to test here

Reviewed By: cipolleschi

Differential Revision: D40142064

Pulled By: cortinico

fbshipit-source-id: 6c65e1030bf3fe1603bfb7d486f8f3fd7d254126

template/_flowconfig

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

template/_gitignore

@@ -31,19 +31,15 @@ local.properties
 *.iml
 *.hprof
 .cxx/
+*.keystore
+!debug.keystore
 
 # node.js
 #
 node_modules/
 npm-debug.log
 yarn-error.log
 
-# BUCK
-buck-out/
-\.buckd/
-*.keystore
-!debug.keystore
-
 # fastlane
 #
 # It is recommended to not store the screenshots in the git repo. Instead, use fastlane to re-generate the

template/android/app/build.gradle

@@ -260,13 +260,6 @@ if (isNewArchitectureEnabled()) {
     }
 }
 
-// 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.implementation
-    into 'libs'
-}
-
 apply from: file("../../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesAppBuildGradle(project)
 
 def isNewArchitectureEnabled() {