units: add reference to new wiki page to all api mount units

man: add Documentation= tags to all kinds of missing units

units: do binfmt magic only when /proc/sys is writable

relicense to LGPLv2.1 (with exceptions) We finally got the OK from all contributors with non-trivial commits to relicense systemd from GPL2+ to LGPL2.1+. Some udev bits continue to be GPL2+ for now, but we are looking into relicensing them too, to allow free copy/paste of all code within systemd. The bits that used to be MIT continue to be MIT. The big benefit of the relicensing is that closed source code may now link against libsystemd-login.so and friends.

units: enable automount units only if the kernel supports them

units: move a couple of units from base.target to sysinit.target

units: make sure we run all early boot units before entering basic.target

mount: add automatic start ordering dependencies for mounts

units: introduce and explain sysinit.target

shorten copyright header of configuration files

units: fix syntax of mount unit files

units: replace a few non-essential API mounts with automount units