tools/libs: move xc_core* from libxenctrl to libxenguest

tools/libs: move xc_core* from libxenctrl to libxenguest

The functionality in xc_core* should be part of libxenguest instead
of libxenctrl. Users are already either in libxenguest, or in xl.
There is one single exception: xc_core_arch_auto_translated_physmap()
is being used by xc_domain_memory_mapping(), which is used by qemu.
So leave the xc_core_arch_auto_translated_physmap() functionality in
libxenctrl.

This will make it easier to merge common functionality of xc_core*
and xg_sr_save*.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>