History View with new entities

[Renegade605]

In the history, if a certain sensor hasn't/didn't exist for the entire time scale requested, it should still match the time scale of the other sensors. ie. In the screenshot below, the time is 18:55 to present, but "Test Humidity Derivative" was created at 19:15. Before 19:15, it should show "unknown" or nothing at all instead of the state it was created with.