Devices options grouped into categories

[JWahle]

Here is what I changed:

• grouped the options on the devices tab into categories (see screenshot)
  • the order and visibility of fields is now fixed and does not depend on occurrence in the default config json or config files
• added silence_threshold and silence_timeout to default config (before, they were invisible by default)
• refactored the creation of the default config into a single method and removed the lowpass filter from the default config (it is not obvious and degrades the sound, if you don't see and remove it)

[HEnquist]

This is a nice improvement! Thanks! I'm merging right away.