base-files: add empty /etc/profile.d which can be filled by distro/machine profile...

base-files: add empty /etc/profile.d which can be filled by distro/machine profile scripts

* used for gtk_im_module.sh in SHR
* would be better to be able to fill it from more sources (maybe put profile.d.machine, profile.d.distro, profile.d directories
  and install all files to target profile.d), is it worth it?
* /etc/profile.d/empty is used to prevent install call not failing because /profile.d/* not found

Acked-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>