Renaming api's and creating helpers. Change password new sp usage.

1. Moving few reusable defines to constants.js. 
2. Earlier we were using usp_user_auth to get the password from DB, but this query is based on string(email)
Since we have the user ID, a new SP to retrieve pwd from user_id has been provided by Aragon. 
3. There have been lot of discussions on understanding the difference between an API and helpers, keeping future scale deployment model in mind we are modifying all the controllers for various actions like email validation, password management, device management to be part of sparkk login helpers.  And anything that returns a readable data as response is perceived as an API moving forward.

Testing with current change set:
1. Basic sanity tests for login moduel- namma auth
2. G+ Signup tested 

PS: Apologies for the out of context branch name, initially started with a different intention.