ofp-util had been far too large and monolithic for a long time. This
commit breaks it up into units that make some logical sense. It also
moves the pieces of ofp-parse that were specific to each unit into the
relevant unit.
Most of this commit is just moving code around.
Signed-off-by: Ben Pfaff <blp@ovn.org>
Reviewed-by: Yifeng Sun <pkusunyifeng@gmail.com>
