Updated deprecated ament_index_cpp API

[ahcorde]

Related with ament/ament_index#104

[ahcorde]

Pulls: ros/pluginlib#289, ament/ament_index#104, ros/resource_retriever#118, ros/ros_tutorials#190, ros-perception/image_common#388, #3011, ros2/rmw_implementation#272, ros2/rmw_zenoh#879, ros2/rosbag2#2268, ros2/rviz#1647
Gist: https://gist.githubusercontent.com/ahcorde/39681e4e2c4ae7c2079f7fbd2e07884f/raw/105720d4ff8bdf2a21aee9708bf35531a754a3b3/ros2.repos
BUILD args: --packages-above-and-dependencies ament_index_cpp
TEST args: --packages-above ament_index_cpp
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/17828

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[ahcorde]

Pulls: ros/pluginlib#289, ament/ament_index#104, ros/resource_retriever#118, ros/ros_tutorials#190, ros-perception/image_common#388, #3011, ros2/rmw_implementation#272, ros2/rmw_zenoh#879, ros2/rosbag2#2268, ros2/rviz#1647
Gist: https://gist.githubusercontent.com/ahcorde/e52f66b6b23f6f749ced640a964517d1/raw/105720d4ff8bdf2a21aee9708bf35531a754a3b3/ros2.repos
BUILD args: --packages-above-and-dependencies ament_index_cpp
TEST args: --packages-above ament_index_cpp
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/17831

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[jmachowinski]

As stated in ament/ament_index#104 I don't like the return type of the new API.
I find that the usage of std::pair instead of a custum struct with good named members reduces the readability of the code a lot.
E.g.

std::vector<std::string> lines = rcpputils::split(result.second, '\n', true);

is way less readable than

std::vector<std::string> lines = rcpputils::split(result.content, '\n', true);