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

[Preclowski]

Hey @alvistar, thank you for your effort! Thats really nice feature. It hurts its stalled just because of conflicts. Could you look into this? Its shame if so nice work is unmerged because of some conflicts. Thank you :)