use pwm_enable if available, otherwise try without it

Bug Fix

What does this MR do?

This MR handles an issue where the hwmon driver doesn't have a pwm_enable file. In this case, the pwm file will be used like normal and only log a warning.

There are also several small improvements, with one important change being that the numbers in hwmon channel names (labels) are not used to determine which channel it is, but instead the entire name is verified. This is because channel names may contain a number different than the actual pwm number.

Related issues

Closes #63 (closed)

Checklist

• Application works as expected when running from source
• AppImage build compiles and runs successfully
• Flatpak build compiles and runs successfully
• There are dependency changes
• tests are successful
• Performance considerations have been taken into account
• This MR is ready to be merged