net/mlx5: add action template management

net/mlx5: add action template management

The action template holds a list of action types that will be
used together on the same rule. The template's actions instances
will be created only when the template bind to the dedicated
group. And the created actions will be saved to each individual
group in order for best performance. The actions in a group will
not be shared with each other unless shared actions are specified.

This commit adds the action template management which stores the
flow action template.

Signed-off-by: Suanming Mou <suanmingm@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>