Template helper should support features, yaml templates do

Feature Requests
1

I am in the process to move my yaml based templates to UI template helpers.

here’s a binary sensor I have created in yaml:

# Intrusion Alarm Device
- binary_sensor:
    - name: "Einbruchsalarm Waschkeller"
      unique_id: "intrusion_alarm_waschkeller"
      icon: >
        {% if states('sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status') in ['idle_off', 'secondary_alarm', 'primary_alarm'] %}
          mdi:shield
        {% elif is_state("sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status", "intrusion_alarm") %}
          mdi:shield-alert
        {% endif %}
      device_class: tamper
      state: >
        {% if states('sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status') in ['idle_off', 'secondary_alarm', 'primary_alarm'] %}
          off
        {% elif is_state('sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status', 'intrusion_alarm') %}
          on
        {% endif %}
      availability: >
        {{ states('sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status') not in ['unknown', 'unavailable', 'None'] }}
      attributes:
        device_state: >
          {% if is_state('sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status', 'idle_off') %}
            Untätig
          {% elif is_state('sensor.rauchwarnmelder_waschkeller_smoke_detector_alarm_status', 'intrusion_alarm') %}
            Einbruch erkannt!
          {% endif %}

As you can see, I am using state based icons - and also some attributes.

Unfortunately, the helper does only support pre-defined icons, and also, it is not possible to add attributes to the sensor.

I would really appreciate if this could be included for the helper