feat(github): added notification dot option

[Video-Nomad]

This option will show a small dot in a specified corner with specified color when there are unread notifications available.
Can also have customizable x and y margin.
It is drawn on the QLabel itself, so changing margin/padding for the .icon style will affect the dot position.

notification_dot:
  enabled: True
  corner: "bottom_left" # Can be "top_left", "top_right", "bottom_left", "bottom_right"
  color: "red" # Can be hex color or string
  margin: [ 1, 1 ] # x and y margin for the dot

[amnweb]

I like it. Thank you!👍