Include ROS 2 Mirror Page

[kscottz]

Per TGC discussion we need to improve mirroring support for ROS 2. Infra PMC will discuss improving infrastructure and circle back with long-term solution.

New page should be analog of the ROS 1 Mirror page.

[ros-discourse]

This issue has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/whats-the-current-state-of-mirrors-are-there-any-ros-2-mirrors/43105/5

[tfoote]

Facebook now has a mirror up of the ros2 repos: https://mirror.facebook.net/ros2/

[kscottz]

Oooh, maybe this would be a good community support item for this week.