Populate database with Fetched contest data

[dr0pdb]

Populate the database with the fetched contest data. Implement insert,query and delete operations.

[VisheshVadhera]

For database, you can consider using Room instead of Content Providers. Has a better API and is way easier to use than Content Providers.

[dr0pdb]

@VisheshVadhera Actually the code for Content Providers is already implemented in a similar project. Hence it's much easier to migrate the code rather than using Room from scratch.