Add a "categorical rectangular circle packing" type

[Kogl1n]

A "categorical rectangular circle packing" visualizes older and more up to date events of different categories affecting a certain amount of entities:

rectangular bars side by side each with a title (position: top or bottom): representing categories. brightness/shade: older -> darker colored circle, new-> brighter colored circle (timestamp: based on creation date or last updated date) circle size: corresponding to affected entities by the event color (optional): a) just one color or b) one color per category or c) one color and a special color (e.g. red) to mark important/urgend events