Provide access to mounted local data storage

[sneumann]

Hi, we should support the case that an institute has a large set of local data in an NFS accessible way,
mounted to the machines running the k8s cluster. First we need to add this as a volume to k8s,
and the containers need to request that volume to some local path.
Secondly, we need to enable adding local paths to a Galaxy data-library,
which requires to enable this feature to admin users in config/galaxy.ini

[app:main]
...
allow_library_path_paste = True

[pcm32]

Great, thanks. I will separate this functionality in two parts though:

1. Ability to set the mentioned setting in the galaxy.ini file. This only requires changes in our base container setup scripts and on helm deployment.
2. Mounting of additional persistent volume claims on Galaxy. This one requires more changes on the base Kubernetes runner inside Galaxy. Doable of course.

We can start with the first and once that is done and tested, move on to the other one.