apacheGH-552 (android) check for build-extras.gradle in the app-paren…

…t directory (apache#553)

as documented in https://cordova.apache.org/docs/en/latest/guide/platforms/android/?#extending-buildgradle

and deal with multiple build-extras.gradle locations

Co-authored-by: David Boho <david.boho@tu-ilmenau.de>
Co-authored-by: Christopher J. Brody <chris.brody@gmail.com>

bin/templates/project/app/build.gradle

@@ -93,11 +93,16 @@ ext {
 // PLUGIN GRADLE EXTENSIONS START
 // PLUGIN GRADLE EXTENSIONS END
 
-def hasBuildExtras = file('build-extras.gradle').exists()
-if (hasBuildExtras) {
+def hasBuildExtras1 = file('build-extras.gradle').exists()
+if (hasBuildExtras1) {
     apply from: 'build-extras.gradle'
 }
 
+def hasBuildExtras2 = file('../build-extras.gradle').exists()
+if (hasBuildExtras2) {
+    apply from: '../build-extras.gradle'
+}
+
 // Set property defaults after extension .gradle files.
 if (ext.cdvCompileSdkVersion == null) {
     ext.cdvCompileSdkVersion = privateHelpers.getProjectTarget()