rosdep update for EOL distros

[mikaelarguedas]

Follow-up of #316 regarding update rosdep DB for EOL distros:
What we would like:

1. make sure the DB is up-to-date when people build the dockerfiles
2. make sure the DB reflects the state of the rosdep database at the time the distro went EOL
3. ideally not update the database for other ROS distros than the one the dockerfile is for

Approaches

1. templates and generated dockerfiles should have the additionnal --include-eol-distros arg passed if the distro is EOL. Draft PR available at add snippet for bootstrapping rosdep docker_templates#75 Implemented in add snippet for bootstrapping rosdep docker_templates#75 and invoke rosdep with --include-eol-distros if ROS distro is EOL #330
2. Brought up the topic with tfoote at Develop more complete EOL policies ros/rosdistro#18296. If we can get a tagged version of the rosdep DB, we can set a custom rosdistro index url and use the DB from that tag
3. Asked the question at Update the database of only a single ROS distribution ros-infrastructure/rosdep#723 implemented in [update] Allow to process single ROS distro, fix 723 ros-infrastructure/rosdep#738