Show timetable on the basis of Roll Number

Add another endpoint in [IITBBSNewsAPI](https://github.com/nightawks/iitbbsnewsapi) to give timetable on providing branch and year. Query this endpoint from iitbbsguide and parse roll number to make the corresponding request to API.

Start by inspecting the IITBBSNewsAPI endpoint patterns and the iitbbsguide flow that handles timetable requests. Trace how the roll number is obtained and how API responses are parsed; done means the API accepts branch and year and the guide requests and presents the corresponding timetable.

Written by the indexing model from the issue text.