add service list to `ros2 doctor --report`

[fujitatomoya]

Description

Add available service list and number of clients/servers to the ros2 doctor --report.

Motivation

service list is also important to know the ROS 2 endpoint connectivity in the report.

Design / Implementation Considerations

Currently ros2 doctor does not show any service list to the report.

root@tomoyafujita:~/ros2_ws/colcon_ws# ros2 doctor -r --exclude-packages
...<snip>
   ROS 2 INFORMATION
distribution name      : rolling
distribution type      : ros2
distribution status    : rolling
release platforms      : {'debian': ['bookworm'], 'rhel': ['9'], 'ubuntu': ['noble']}

   TOPIC LIST
topic               : /chatter
publisher count     : 1
subscriber count    : 1

this feature adds the SERVICE LIST along with TOPIC LIST above.
corresponding rclpy APIs are already available, so this can be straight-forward to add ServiceCheck inherited by DoctorCheck class.

Additional Information

via ros2 doctor -r, it can generate the QoS incompatibility status between publishers and subscriptions. User application can be also notified via QoS incompatibility event on endpoint creation, so user might already know that there is a incompatibility QoS so that they cannot communicate each other.

with current provided API for service client and server, we cannot do this yet. for doing this,1st we need to complete #916, so QoS incompatibility check is out of scope of this feature request.

[fujitatomoya]

@InvincibleRMC probably we want to work on this 1st? i think this is really straight-forward to add along with TOPIC LIST, maybe adding the test for TOPIC LIST and SERVICE LIST would be ideal.