Create a Data volume to store forjj credentials information for forjj maintain to work from docker

[clarsonneur]

user story

As soon as forjj is going to be used by the ci to run forjj maintain on the infra repository, we need forjj to be runnable from docker (docker/swarm/mesos/kubernetes/...) So, we need to create a volume that will be mounted to get the forjj credentials information so that forjj maintain can operate.

note that we could use a default mount type, s that Forjfile can be used without need add extra parameters.

forjj should be able to run in dood context as well. So the list of dood docker options should be detected by forjj to consider that it will run in dood context.

[clarsonneur]

I may not use this approach for forjj pipelines...

Secrets are now encrypted. So, I could put the file in Jenkins_home and set the key as a Jenkins credential.

I probably need to attach the credential to a folder so that other jobs could not access such secrets.