history-graph: add a per entity configuration to select the type of graph to override the automatic selection based on the presence of UOM

[fduchatelet]

Problem description:

Since 2022.9, the zone integration added an UOM to their sensors and it breaks one of my dashboard:
This is a consequence of the home-assistant/core#78422 issue in core

The result is this: the fourth history bar has been replaced with that monstrous graph

Having a way to specify the kind of rendering we want for each entity would be awfull.
It would save me the burden and resources of defining a template sensor without UOM.

Something like this:

type: history-graph
entities:

• entity: zone.home
  name: test-bar
  render: bar
• entity: zone.home
  name: test-graph
  render: graph