Improve support to Hi-Fi systems by adding support to speaker device_class

[fulippo]

When controlling an Hi-Fi system via IR, some basic controls like next track, previous track, play/pause are missing because the device_class defaults to TV. We allow HA to identify the device as a MediaType.MUSIC by allowing to specify the device_class as speaker in the configuration.

A better control for current state initial state is also implemented defaulting to IDLE instead of ON. This allows Home Assistant to set the media player in a neutral state that is required to correctly display the control buttons.

To set the correct device class just use a configuration like this in HA:

media_player:
  - platform: smartir
    name: Stereo Pioneer
    unique_id: stereo_pioneer
    device_code: 99999
    device_class: speaker # this is required
    controller_data: remote.universal_remote
    power_sensor: binary_sensor.stereo

This is an example of the device's working configuration that I've tested with this version of the player:

{
    "manufacturer": "Pioneer",
    "supportedModels": [
      "A-Z370"
    ],
    "supportedController": "Broadlink",
    "commandsEncoding": "Base64",
    "commands": {
        "off": "JgDYAAABD4oPExEzDzUQEhASEDQQExA0EDQRERERDzYQMxERETQQEg8TEBIRMxA1EDQPEhESEREQNQ80ERERERESEDUONREzEAADggABD4oPExA0ETMREhASEDQQEhA1DzUQEhAREDURMxASDzURERERERIQNBA0ETMQEhATEBIQMxE0EBIQEhASEDQRNBA0EAADgQABEIkRERE0EDQQExASETIQEw82DzQREhASDzUQMxATEDQQEw4TEBIQNQ81DzYOEhATERIONg81DxMPEhESDzUQNBA1DgANBQ==",
        "on": "JgDYAAABD4oPExEzDzUQEhASEDQQExA0EDQRERERDzYQMxERETQQEg8TEBIRMxA1EDQPEhESEREQNQ80ERERERESEDUONREzEAADggABD4oPExA0ETMREhASEDQQEhA1DzUQEhAREDURMxASDzURERERERIQNBA0ETMQEhATEBIQMxE0EBIQEhASEDQRNBA0EAADgQABEIkRERE0EDQQExASETIQEw82DzQREhASDzUQMxATEDQQEw4TEBIQNQ81DzYOEhATERIONg81DxMPEhESDzUQNBA1DgANBQ==",
        "volumeDown": "JgDcAAABEIoQEhA0ETMQEhESEDMQEhE0EDQREhARETMRNBASETMREREzEDUPEw81EREREQ8TEBMQEhASEDQQEg81EDUQMxE0EAADhgABEIkRERE0EDQQEhASETMQEhA1EDMREhERETMQNQ8SETQRERA0EDQQEhA1EBIPExASEBMPEhERETQQEhA0EDQRMxA1EAADhgABEIkREQ82EDMQEhESETMQEhA0EDQREhASEDQQNBERETQQEhAzETQREQ82DxMQEhARERIRERASEDUQEhAzETQQNBA0EAACtAQADQU=",
        "volumeUp": "JgAgAQABD4oQEw80ETMPFBASETIQExEzEDUPEhATDzUQNBARETQQEhASETQREBE0DxMQEhASDxMRMxASDzYQEhA0EzEQNRAzEQADhgABEIkRERA1DzUPEhESEDQQEhA0ETMREg8UDzQQNBERDzYPExAREDUQEhA0EBMQEhARERIQNA8TDzUQEhEzEDUQMxA1EAADhgABEIkQExEyEDURERASDzYQERE0EDQPExEQETQRNA8TEDQQEhERETMQEw80EBIREhASEBIPNRERETMQEw81EDQQNBA1DwADhwABEIkQERE0ETQPExASEDQQEhA0EDQRERERETQQNQ8SETMPExATDzUQERA1DxMQEg8UDxIRNA8TEDUPERE0EDQQNQ80EQANBQ==",
        "play": "JgDYAAABEIkRERA1EBIQERASETQQEhA1EDMRERA1EDMRNBEREDUQEg80ETQQNBASEDQRERATEBIQEhAREBMRMxASEDQQNBE0EAADjAABEYgRERA1EBERERESEDQQEhA0ETMQExA0EDMRNBASEDQQEhE0DzUQMxESETMQEhATEBEQEhESEBIQNA8TEDQRMxA1DwADjQABEIkQEhA0EBIQEw8TEDQPEhE0DzUQEw80ETQQNA8TEDQRERE0EDMRNBERDzUQExAREBIRERATEBIQMxESETMQNRAzEAANBQ==",
        "pause": "JgDYAAABEIkQEhA0EBIRERASETQQEhAzETQREQ82EDMRNBEREDQQExARERERERA1EDMREhEREREQNRAzETMSERASDzYQMxE0EAADjAABD4kREhA0EBIQEhEREDQQEw81EDQREREzEDUQMxESEDQPExASERERERE0EDQQERESERERMxA1EDMREg8TDzUQNBEzEAADjAABEIkRERE0EBIQEhASETMQEhA1EDMREhEzEDQQNBERETQQEhASDxIREhEzDzYQEg8SERERNBA0EDQRERERETQQMxE0EQANBQ==",
        "stop": "JgCUAAQABLsAARCJEBIQNBEREREREhA0EBIQNBEzEBMQNBA0ETMQEhA0EREQEhE0EDQQEhEzEBIQExASEDMREhERETMQEw80ETMQNRAAA40AARCJEBIQNBASERERERE0EBIQMxE0EREPNhAzETQQEhA0EBIREREzEDUPExA0ERERERASEDUQERASETQQEhA1EDMQNBEADQU=",
        "previousChannel": "JgDYAAABDosQEhAzERIRERASDzYPEhEzETQQEhA0ETMQNRASEDMREhA0DxMQEhASETMQExASEBIQERE0DzUQNBEREjMPNQ81EQADfgABEYgPExA0EBIRERESEDQPExA0ETMQExAzETQQNA8TEDQRERE0EBIPEw8SETQQEhASEBMQEREzETQQMxESETMPNhAzEAADgAABEIkPExA0EBIREREREDUQEhAzETQQEhA0ETMRNA8TEDMREhA0EBIPFBARETMREg8TEBIQEhA0ETMPNhAREDUQNA81EQANBQ==",
        "nextChannel": "JgDYAAABEYgQEw81EBERERESEDQQExAzETQPExA0DzURMxESEDMRERESEREQEhASEDQQEhEREBMPNRA0ETMQNRASEDMRNA81EAADfwABEIkREhA0EBIQEw8SETMREhA0DzUREREzEDUQMxESETMQEhATDxIRERERETQQEhASEBIRMxA1DzQQNREREDQQNBA0EAADgAABEIkQExAzEREREg8TEDQQEhEzEDUQEhAzETQQNBATEDMRERESEBIQEg8TEDQQEhASEBMQNBA0ETMQNRARETQQNBA0EAANBQ==",
        "sources": {}
    }
}