Modify the rendering code to render the given viewport

[bhavya-tech]

Current behaviour:

• All the celery events are first drawn on the InteractiveArea and then interactive area handles the panning to render only the part which is shown on screen.

This has two drawbacks:

1. Higher resource consumption.
2. We cannot render the events on demand (i.e. we need the whole data to render)

The second drawback is a roadblock for this new feature where we will dump the events in a database and let users see past events as needed.
In this, we cannot load the whole database in our app and then render it. We need to load events on demand and render only that part.