openvswitch: rework packaging

openvswitch: rework packaging

New scheme mainly provides three packages: openvswitch,
openvswitch-ovn-north, openvswitch-ovn-controller.  These should fit
most usage scenarios.  Other subpackages like openvswitch-libXXX
etc.  are there for dependency management and are hidden from the
menu.

Many python and shell scripts are removed in this revision.  Most of
them cannot run out of box at all for lack of dependencies.  Others
being legacy ones are not that useful now.  Add them back at later time
when real need appears

Below are a simple listing of additions

 - initscript now incorporate also ovn north and controller support
 - ovn-ctl and ovs-ctl can be invoked directly from within $PATH

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>