Allow arbitrary placement of entity details

[igorsantos07]

The README exposes a simple example on how to use auto-entities to create a grid with standalone entity cards, which is an awesome starter point.

However, if you want to use different cards, you're stuck to anything that can receive the entity: prop. The only way to use, for instance, a decluttering-card template is to use the double-auto-entities hack where one of the filters is a template that returns a dict with the details you need for the card...... Which is (1) ugly AF, (2) terrible to write and debug, (3) very confusing and (4) not performant at all.

A suggestion would be to do it like this:

filter:
  include:
    - entity_id: "sensor.*_battery"
      options:
        type: custom:decluttering-card
        template: my_graph_template
        variables:
          - entity: "[[entity_id]]"
          - title: "[[friendly_name]]"

Bonus points:

• any chance this idea could be jinja-templated? This would effectively allow people to do their own replacement rules, killing off the dreaded #166
• another option is try to follow what was done in custom-ui, which allows us to write basic JS to achieve some value manipulation