Clickable notifications

[dezemand]

Currently, the notifications do not provide any action handlers when clicking on them. It would be nice if we could catch the click event when the user clicks on the notification. For example, show the user more information about the notification after clicking on it.

In addition to this, some extra styling would be necessary, such as a hover animation and using the pointer css value for the cursor. This can already be done currently using the Styles API, but it would be nice if styling is applied automatically if the notification is clickable.