Move Play Store JSON key outside the repo

This is a good security practice. In noticed the key location while
looking into the CI failure at
https://buildkite.com/automattic/simplenote-android/builds/388

Google Api Error: Invalid request - The caller does not have permission

I doubt the error is due to the key location, but since I'm looking into
the key, I thought I might as well fix its location and try again.

.configure

@@ -1,7 +1,7 @@
 {
   "project_name": "Simplenote-Android",
   "branch": "trunk",
-  "pinned_hash": "2c5509d08ff9b9620381f4dc602fc2e5edcfcb40",
+  "pinned_hash": "1761b0a77a5371f9127c5d0575c90f938d864537",
   "files_to_copy": [
     {
       "file": "android/simplenote/Simplenote/gradle.properties",
@@ -25,7 +25,7 @@
     },
     {
       "file": "android/Simplenote/google-upload-credentials.json",
-      "destination": ".configure-files/google-upload-credentials.json",
+      "destination": "~/.configure/simplenote-android/secrets/google-upload-credentials.json",
       "encrypt": true
     }
   ],

fastlane/Fastfile

@@ -46,7 +46,7 @@ STORE_METADATA_SOURCE_DEFAULT_FOLDER = File.join(STORE_METADATA_SOURCE_FOLDER, S
 RELEASE_NOTES_PATH = File.join(STORE_METADATA_SOURCE_DEFAULT_FOLDER, 'changelogs', 'default.txt')
 RELEASE_NOTES_SOURCE_PATH = File.join(PROJECT_ROOT_FOLDER, 'RELEASE-NOTES.txt')
 
-UPLOAD_TO_PLAY_STORE_JSON_KEY = File.join(PROJECT_ROOT_FOLDER, '.configure-files', 'google-upload-credentials.json')
+UPLOAD_TO_PLAY_STORE_JSON_KEY = File.join(Dir.home, '.configure', 'simplenote-android', 'secrets', 'google-upload-credentials.json')
 
 GRADLE_APK_OUTPUT_PATH = File.join(BUILD_FOLDER, 'outputs', 'apk', 'release', 'Simplenote-release.apk')