English staging app name.

build.gradle

@@ -357,6 +357,9 @@ android {
             java.srcDirs = ['test/unitTest/java']
             resources.srcDirs = ['test/unitTest/resources']
         }
+        staging {
+            res.srcDirs = ['staging/res']
+        }
 
         website.manifest.srcFile 'website/AndroidManifest.xml'
     }

staging/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<resources>
+  <string name="app_name">Signal Staging</string>
+</resources>