Update/Optimize workflow for Generate/Decrypt Keystore- Android

[code-jenn-or]

When generating the Keystore you will likely be running Fastlane from the root directory of your project, however, when you are decrypting the Keystore file it will most likely be run from the android folder from the lane (on CI).
With this in mind, we need to determine the file path based on this information for not only creating the Keystore files, but also decrypting/exporting and then copying the file.