Create explicit init and login methods

[xpt1x]

As UIMS has imposed restrictions for accessing UIMS data by protecting Login mechanism with a captcha

This library at current structure can't comply to it, so we should now create explicit initialize and login method for the session instance where:

• initialize(credentials) - will initialize the instance with relevant user login data (like credentials) and will return a captcha url
• login(captcha) - will have captcha as a parameter, after this session will be a valid session and can properly access other properties like full_name and attendance otherwise an error will be thrown if session is not valid (i.e improperly init)

Projects relying on this library can present user with the captcha image provided by initialize to solve and call login method with answer to this captcha

Ofcourse naming can be changed but it should be a two step process now