Allow to setup a Gradle Enterprise instance via an external script

Summary:
This diff allows to setup a Gradle Enterprise instance
either locally or on CI via an external Gradle script.

I've create a `.sample` script that users can copy to
start setting up their GE instance, should they have one.

Moreover, it applies the `com.gradle.enterprise` Gradle
plugin by default. This has the positive side effect of
not invalidating build cache for the included build if
you happen to pass the `--scan` flag in OSS (as the
classpath isn't changed).

Changelog:
[Android] [Added] - Allow to setup a Gradle Enterprise instance via an external script

Reviewed By: mdvacca

Differential Revision: D33582388

fbshipit-source-id: 0c2f073cf7a8e39963b0adfc3b339b14c1e7759b

gradle/gradle-enterprise.gradle.kts.sample

@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+// You can use this script to configure the gradleEnterprise{} block in your build.
+// You need to rename this file to ./gradle/gradle-enterprise.gradle.kts in order for
+// this to be processed.
+extensions.getByName("gradleEnterprise").withGroovyBuilder {
+    setProperty("server", "https://your-gradle-enterprise-instance.example.com")
+    getProperty("buildScan").withGroovyBuilder {
+        "publishAlways"()
+        "tag"(if(System.getenv("CI") != null) "CI" else "Local")
+    }
+}

settings.gradle.kts

@@ -22,3 +22,14 @@ include(
 // Include this to enable codegen Gradle plugin.
 includeBuild("packages/react-native-gradle-plugin/")
 
+rootProject.name = "react-native-github"
+
+plugins {
+    id("com.gradle.enterprise").version("3.7.1")
+}
+
+// If you specify a file inside gradle/gradle-enterprise.gradle.kts
+// you can configure your custom Gradle Enterprise instance
+if (File("./gradle/gradle-enterprise.gradle.kts").exists()) {
+    apply(from = "./gradle/gradle-enterprise.gradle.kts")
+}