Use serialization utils from rde for ini configurations

[Frewacom]

Instead of using our own (very basic) alist to ini serializer, we can use the one from rde.

For example, it can be implemented like this, and then used as follows (see this repo):

   (service
    home-mako-service-type
    (home-mako-configuration
     (package mako)
     (config
      `((sort . -time)
        (actions . 0)
        (icons . 0)
        (font . "Iosevka Light 14")
        (text-color . "#000000")
        (background-color . "#FFFFFF")
        (border-color . "#721045")
        (layer . overlay)
        (border-size . 2)
        (padding . 10)
        (width . 400)
        (group-by . app-name)
        (ignore-timeout . 1)
        (default-timeout . 3500)
        ((mode dnd)
         .
         ((invisible . 1)))))))