Add SMART self-test metrics

[alvistar]

This PR adds support for monitoring SMART self-test results, providing visibility into the health and reliability of storage devices. The implementation supports both ATA and SCSI devices.

New metrics:

• smartctl_device_last_self_test: Status value of the most recent self-test
• smartctl_device_last_self_test_info: Detailed information about the most recent self-test including type, status description, and when it was performed

The implementation includes:

• Support for both ATA and SCSI device self-test logs
• Comprehensive test coverage with real-world device data
• Modified smartctl command to include self-test logs

Testing:

• Added test cases using real device data from:
  • Seagate Exos X16 (ATA)
  • Seagate ST18000NM004J (SCSI)
• Implemented testing framework for metric collection and validation

[robbat2]

Can you include examples of the output metrics in the PR?
Esp. I want to be able to easily see how it changes when successive tests are run on a device

[k0ste]

@alvistar the DCO is missed, look to the CI results

[daveiit]

Hi!
would be nice to merge if the only issue are the conflicts.

[k0ste]

Hi! would be nice to merge if the only issue are the conflicts.

Impossible to merge before author resolve conflict's and pass CI