feat: customization of temperature sources

We currently get temperature from 3 sources: SCT, Smart Attr 194, and what smartctl reports in the top level temperature key, which comes from the device General Purpose Log (see https://github.com/smartmontools/smartmontools/issues/609).

Drives often don't correctly report all 3 (see #972), so we need config options per-drive to control which are used. Right now SCT can be discarded via GUI option (stored in sqlite db), but it's system-wide, not per drive. This will likely end up being a breaking change, and should probably wait until #1022 is done so we support uuid keys for devices