Move all of init to libinit

I'd be not doing this for a while since some of this code doesn't
compile on host and libinit previously did.  But after realizing
the property_service.cpp (libinit) references symbols in init.cpp
(init) and seeing a new linker error crop up due to that, it's time to
make the fix.

My only hold out previously was that libinit compiled on host bionic
and some of init (builtins.cpp, etc) do not, however given that we
don't actually have host bionic support or host bionic init tests,
that isn't a good reason.  We can and should mock out the libraries
that aren't available with host bionic when ready.

Test: build, unit tests, boot
Change-Id: Ie49362ddb637924efc272540a4f32b693643fcdc