The ALSA module was essentially removed in 3eeff547, with the main
motivation of avoiding confusion as to what `sound.enable` really meant.
As that could be achieved with a simple rename, this change brings back
the module in full force under the `hardware.alsa` namespace (with clear
beware signs for the pulse and pipewire folks) and adds a lot of useful
extra features. These include
- `defaultDevice` to set the default playback and capture devices
- `cardAliases`,`deviceAliases` to assign meaningful names to sound cards
and devices (instead of say, `hw:0,1`)
- `controls` to create virtual volume controls
- `enableRecorder` to easily configure a loopback device to record
the computer audio
- fixes to the udev restore rules
c8a84a01d5