The service can run unprivileged -- by using capabilities -- and the
uid/gid can be dynamically allocated since there are only a handful of
state files.
This change improves the overall security of the service by leveraging
systemd's hardening and getting rids of `nogroup` and the initial root
permissions (before the daemon drop privileges).
There are circumstances where running secondary DHCP servers in
non-authoritative mode is advantageous. Retain the previous
authoritative behavior as a default.
A centralized list for these renames is not good because:
- It breaks disabledModules for modules that have a rename defined
- Adding/removing renames for a module means having to find them in the
central file
- Merge conflicts due to multiple people editing the central file
Using pkgs.lib on the spine of module evaluation is problematic
because the pkgs argument depends on the result of module
evaluation. To prevent an infinite recursion, pkgs and some of the
modules are evaluated twice, which is inefficient. Using ‘with lib’
prevents this problem.
