ivi-shell: make ivi-layout.c as a part of ivi-shell.so

ivi-layout.so is separately built and loaded by using dlopen with
RTLD_GLOBAL. This was because these apis defined in ivi-layout.so shall
be used by ivi-modules; e.g. hmi-controller. This shall be improved that
a struct ivi_layout_api contains the whole exported API as function
pointers to be exposed as module_init.

This patch alone builds, but loading controller modules at runtime
failes. This failure will be fixed by following patches.

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>