net/mlx5: HWS, added matchers functionality

Matcher object encompasses all the building blocks that are
needed in order to perform flow steering of a given flow:
 - flow table that serves as entering point of this matcher
 - Rule Table Context (RTC) objects to hold ll the Steering
   Table Entries (STEs), both for matching the flow and for
   performing actions
 - rules that describe the set of matching parameters for a
   flow and actions to perform in case of a hit.
This patch adds implementation of matchers handling in HWS.

Reviewed-by: Itamar Gozlan <igozlan@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>