[FR] add device info metric

[PhilipMay]

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# HELP smartctl_device Device info
# TYPE smartctl_device gauge
smartctl_device{ata_additional_product_id="HC7020E0",ata_version="ATA8-ACS, ATA/ATAPI-7 T13/1532D revision 4a",device="/dev/sda",firmware_version="1.03",interface="sat",model_family="Plextor M3/M5/M6 Series SSDs",model_name="PLEXTOR PX-128M6S",protocol="ATA",sata_version="SATA 3.1",serial_number="P02448109994"} 1.0
smartctl_device{ata_additional_product_id="unknown",ata_version="ACS-2 (minor revision not indicated)",device="/dev/sdc",firmware_version="82.00A82",interface="sat",model_family="Western Digital Red",model_name="WDC WD20EFRX-68EUZN0",protocol="ATA",sata_version="SATA 3.0",serial_number="WD-WCC4M4VX3C69"} 1.0
smartctl_device{ata_additional_product_id="unknown",ata_version="ACS-2 (minor revision not indicated)",device="/dev/sdd",firmware_version="82.00A82",interface="sat",model_family="Western Digital Red",model_name="WDC WD20EFRX-68EUZN0",protocol="ATA",sata_version="SATA 3.0",serial_number="WD-WCC4M6DCPPC7"} 1.0
smartctl_device{ata_additional_product_id="unknown",ata_version="ACS-4 (minor revision not indicated)",device="/dev/sde",firmware_version="SBFK71E0",interface="sat",model_family="Phison Driven SSDs",model_name="KINGSTON SA400S37120G",protocol="ATA",sata_version="SATA 3.2",serial_number="50026B778224F6E1"} 1.0
smartctl_device{ata_additional_product_id="unknown",ata_version="ACS-4 (minor revision not indicated)",device="/dev/sdf",firmware_version="SBFK71E0",interface="sat",model_family="Phison Driven SSDs",model_name="KINGSTON SA400S37120G",protocol="ATA",sata_version="SATA 3.2",serial_number="50026B778224F53C"} 1.0
smartctl_device{ata_additional_product_id="unknown",ata_version="ATA8-ACS, ACS-2 T13/2015-D revision 3",device="/dev/sdb",firmware_version="2.28.20",interface="sat",model_family="SandForce Driven SSDs",model_name="OCZ-VERTEX3",protocol="ATA",sata_version="SATA