Rebooting to set change the kernel command line to set some udev parameters is
inconvenient. Let's allow setting more stuff in the config file.
Also drop quotes from around "info" in udev.conf. We need to accept them for
compatibility, but there is no reason to use them.
We generally have separate man pages for all configuration files.
In this case udev.conf was already described in systemd-udevd.service(8),
but it was hard to find. Docbook makes it hard to add a .so link from
a different section, so describe udev.conf in its own page.
