separate rosconsole

[dirk-thomas]

As a consequence of ros/ros_comm#1206 rosconsole needs to be separated from the ros_comm repository since rosbag_storage wants to use pluginlib which itself depends on rosconsole.

The following list of changes is related to that separation:

• document that pluginlib and therefore also class_loader are dependency of the ros_comm repo which moves them from the "ros_base" variant into the "ros_core" variant: separate rosconsole ros-infrastructure/rep#173
• update the metapackages to reflect that change: separate rosconsole metapackages#24
• create new https://github.com/ros/rosconsole repository with a melodic-devel branch (same as ros_comm)
• remove all other packages from the rosconsole repo and move the package to the root
• release a new upstream release of rosconsole for Melodic: 1.13.7
• create a new gbp repo for rosconsole (https://github.com/ros-gbp/rosconsole-release)
• bloom-release rosconsole into Melodic (removing the release from the "old" location): extract rosconsole #17920
• remove rosconsole from ros_comm on the melodic-devel branch: remove rosconsole ros_comm#1405
• release a new upstream release of ros_comm for Melodic: 1.14.0
• bloom-release ros_comm into Melodic (without rosconsole): ros_comm: 1.14.0-0 in 'melodic/distribution.yaml' [bloom] #17921
• move all rosconsole tickets / PRs from the ros_comm repo to the new repo
• Add documentation about move to http://wiki.ros.org/melodic/Migration: http://wiki.ros.org/action/info/melodic/Migration?action=diff&rev2=9&rev1=8