Dependencies:
 - Executed on all nodes. On the storage nodes, the katrin_storage role should be executed before
 - Unless docker_storage_vg is defined, it will try to detect the first VG with the space available and which is not equal to katrin_data_vg

Parameters:
 docker_storage_vg / docker_storage_device: Configures VG to use for docker images
    - If docker_storage_vg is not set it will try to detect the first VG with space available and which is not listed in the 'docker_exclude_vgs'
    - If such VG is not found, it will create VG on the specified device
 docker_exclude_vgs: Lists VGs which should not be used to host Docker volumes
 docker_min_size: Specifies the minimum size requirement of Docker LV
 docker_volume_size: Adjust the size of Docker LV
 
Facts:
 - Nope

Actions;
 - Detects or creates Docker VG and creates inside the 'docker-pool' LV (autogrowing). The initial size may be given with docker_storage_size
 - Installs docker, configures LVM storage backend, and enables docker service