net/mlx5: Add a no-append flow insertion mode

If no-append flag is set, we will add a new FTE, instead of appending
the actions of the inserted rule when the same match already exists.

While here, move the has_flow_tag boolean indicator to be a flag too.

This patch doesn't change any functionality.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanmox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>