Adds an input aligner filter

[saarnold]

This adds a new message filter implementation allowing to align multiple inputs in time and calling their callbacks in the right order.
This filter aims to handle the common case in which messages on different input streams arrive with different delays, due to processing times or the used transport channel.
This is a feature that was missing so far.

[ahcorde]

Thank you for your great contribution, I did an initial pass, I will do a deeper review, meanwhile I would love to have more eyes here. @clalancette do you mind to take a look ?

[ahcorde]

Do you mind to add some documentation about this new feature under the doc folder ?

[ahcorde]

Pulls: #148
Gist: https://gist.githubusercontent.com/ahcorde/a884db5657005fa29d85aedc926e6297/raw/44615e18a54c5f9df888d0fe3486f93401824ff5/ros2.repos
BUILD args: --packages-above-and-dependencies message_filters --packages-above-and-dependencies message_filters
TEST args: --packages-above message_filters --packages-above message_filters
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/14663

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

[ahcorde]

Pulls: #148
Gist: https://gist.githubusercontent.com/ahcorde/74f63f0464d1cfe65afbb106fac8f00b/raw/44615e18a54c5f9df888d0fe3486f93401824ff5/ros2.repos
BUILD args: --packages-above-and-dependencies message_filters --packages-above-and-dependencies message_filters
TEST args: --packages-above message_filters --packages-above message_filters
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/14665

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

[ahcorde]

Do you mind to take a look to the new windows warnings ? https://ci.ros2.org/job/ci_windows/22677/msbuild/new/

[ahcorde]

@saarnold friendly ping