Incompatible changes due to Database Migration

[yashovardhan99]

The project has decided to switch to using sqlite as it's database instead of duckdb. The migration was completed via #24.

As such, all users are advised to manually migrate their database before updating to the latest development version of NiveshPy. Alternatively, you can delete and re-populate the database after updating the app.

Please keep in mind that further major changes are expected as part of #27. Please keep these in mind before continuing to work on this project.

[yashovardhan99]

Please note that this change is now released in version 1.0.0.a2. To discuss more, go to #77