allow more-info to point to other entities

[Mariusthvdb]

Additional context
Add any other context or screenshots about the feature request here.

following our discussion in https://community.home-assistant.io/t/lovelace-button-card/65981/1141?u=mariusthvdb

please add the option for a more-info action to point to other entities than the entity holds.

previously on Tiles:

entities:
  - entity: device_tracker.life360_name
    templates:
      background: >
        if (state === 'home' || state === 'not_home') return 'url(\"/local/tiles/family/name_' + state + '.png\")';
        return 'url(\"/local/tiles/family/name_' + entities['sensor.name_location_picture'].state + '.png\")';
      style: >
        if (state === 'home') return 'background-color: #008000';
        if (state === 'not_home') return 'background-color: #808080';
        return 'background-color: #643aac';
    more_info: group.name

[iantrich]

I was planning on adding this to the common custom-card-helpers in the near future; so lets table this until we convert to those helper functions