add show_state option for picture-glance entities

[iantrich]

Continues the great work by @isabellaalstrom in #3321

Closes #3901

Docs: home-assistant/home-assistant.io#10916

[bramkragten]

On glance we have this option on the card, and here we do it on the entity?

[iantrich]

I didn't personally like the look of a state under an icon that already relays the information; e.g. a light, but having it under the sensor did look good. So I agreed with @isabellaalstrom that it should be at the entity level

[bramkragten]

Isn't that the same on glance?

[iantrich]

I could introduce the option at the entity-level for glance as well if that's what you're getting at. Would leave the card-level option to avoid a breaking change and let the entity-level option override it. Could add the same to picture-glance.

[bramkragten]

I would prefer that if we want it on entity level

[iantrich]

@bramkragten you see anything else on this one? Thanks.