Added application flavor and applied convention plugin to all module

Please Add Screenshots If there are any UI changes.

Please make sure these boxes are checked before submitting your pull request - thanks!

[x] Apply the MifosStyle.xml style template to your code in Android Studio.
[x] Run the unit tests with ./gradlew check to make sure you didn't break anything
[ ] If you have multiple commits please combine them into one commit by squashing them.

openMF / android-client