Add type hash support (pub/sub only)

[JEnoch]

Add support of ROS 2 type hash set by rmw_cyclone_dds in USER_DATA QoS.

What this PR does if $ROS-DISTRO >= iron:

• Declares the Reader/Writer on ros_discovevry_info topic with the expected type hash (hard coded) in USER_DATA QoS
• For Topics Publishers/Subscribers: adds the discovered USER_DATA QoS to the encoded QoS already present in the Liveliness Tokens.
• For Actions Services/Clients:
  • declare the Readers/Writers on status topic with the expected type hash (hard coded) in USER_DATA QoS
  • declare the Readers/Writers on feedback topic with an pseudo-type hash (hard coded) in USER_DATA QoS
    (currently rmw_cyclonedds_cpp only checks the presence of a type hash, not the compatibility...)

The propagation of type hashes for Services and Actions is not implemented in this PR.
A type hash encoded in USER_DATA QoS is 81 characters/bytes ("typehash=RIHS01_<64bytes>;"). For a Service on DDS, we need to propagate the type hashes for both the Request and Response topics (162 bytes). For an Action it would be 8*162=1296 bytes. Even if the Zenoh Liveliness Tokens have no size limit, this would add a burden on the discovery phase.

Moreover, at this stage rmw_cyclonedds_cpp set the type hash in USER_DATA for each DDS Reader/Writer, but on discovery it check if it's present only for Topics Pub/Sub, not for Services.

fix #290

[gmartin82]

Looks good apart from the compiler reporting unused code.

Tested with ROS2 Jazzy and warnings no longer show.

[gmartin82]

Looks good.