find_program() did not detect the eldbus-codegen binary in a given
prefix. Which is a situation we have on Jenkins builds. Make it an
option that can be set like we already do with edje_cc.
If there is a more meson-like approach to this I do not know feel free
to enlight me.
this module is not loaded by any other (dependency) nor is it loadable
via the gui - no module/desktop there thus will be hidden... so it's
useless/unused... thus remove it as its not usable by users.