Add click event to entity widgets

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

An entity widget depicts the current value of an entity. I somehow expect clicking on the widget to be guided to a more detailed page of the home assistant companion app. E. g. to see a graph of said entity with historical values.
**Describe the solution you'd like**

As people expect different actions, a generic solution, within the setup, enable the user to define an action, might be the best way to go. A on-click parameter could be set by default to "trigger update" as it is right now. However, one could also select "open dashboard", "open entity graph of the last x hours" and potentially other actions.
That would give people a lot of customisation options.

**Describe alternatives you've considered, if any**

Open the app, select the dashboard resp. the entity graph.

**Additional context**