BREAKING: Use fully qualified attribute names

[Meatballs1]

Resolves #72

This is a breaking change that means manually configured MQTT configurations in HA will need updating. I don't have much experience running this with HADiscovery enabled so would be good to get some feedback if further changes are required for that.

For example the SetpointTemperature in the following:

number:
  - name: "Set Point Temperature"
    unique_id: "freezer_set_point_temperature"
    state_topic: "homeconnect/freezer/state"
    value_template: "{{ value_json.SetpointTemperature }}"
    command_topic: "homeconnect/freezer/set"
    command_template: "[{\"uid\":8198,\"value\": {{ value }} }]"
    min: -26
    max: -16
    icon: mdi:snowflake-thermometer
    unit_of_measurement: "°C"
    availability:
      - topic:  "homeconnect/LWT"
      - topic:  "homeconnect/freezer/LWT"
    availability_mode: all
    device:
      identifiers: "freezer"

Needs to become:

number:
  - name: "Set Point Temperature"
    unique_id: "freezer_set_point_temperature"
    state_topic: "homeconnect/freezer/state"
    value_template: "{{ value_json['Refrigeration.Common.Setting.Freezer.SetpointTemperature'] }}"
    command_topic: "homeconnect/freezer/set"
    command_template: "[{\"uid\":8198,\"value\": {{ value }} }]"
    min: -26
    max: -16
    icon: mdi:snowflake-thermometer
    unit_of_measurement: "°C"
    availability:
      - topic:  "homeconnect/LWT"
      - topic:  "homeconnect/freezer/LWT"
    availability_mode: all
    device:
      identifiers: "freezer"