Install systemd into the default path

Mer installs systemd on /lib, instead we want the default which is
/usr/lib. Some day we will implement UsrMove completely so this feels
just right.

Besides, why lose time fighting defaults that are right for us?
Remove docs subpackage

There's no point in having this subpackage since it's empty.
Remove Python dependencies from analyze

systemd-analyze is rewritten in C from a long time now.