enhancement: custom icons/images in place of rank display

[Jay-Karia]

Is your feature request related to a problem? Please describe.

Add custom images to the rank display.
This could increase the asthetics of the card.

Describe the solution you'd like

A new feature: to add icons/images to the Stats Widget in place of the rank display.
There is an option to add a github logo there, and there should be more pre built images to add.

A new api parameter should be introduced: &rank_icon=

Additional context

A unique image could be assigned to every theme, and on applying the theme, it's respective logo could be displayed (optional)