[Feature Request] Shared persistent mountpoints / volumes

Is your feature request related to a problem? Please describe

For certain types of projects (mostly CMS - WordPress, typo3, sulu... but not only) would be less hustle to have one central database and one central asset storage, instead of recreating the database and copying assets for each new workspace.
and thus having persistent storage - a volume, which could be mounted to a workspace, or even shared within the team, would be helpful.
As a concrete example: if I want to work on a new Github issue, I don't want a clean database, I would prefer to have the same DB content and also assets in the uploads folder, as on the master workspace. So this way I would just select the desired volume and mount it to my issue workspace.

Describe the behaviour you'd like

Similar behaviour as Docker volume or Kubernetes PVC - a possibility to create persistent volumes, which could be then mounted to any workspace or duplicated and then mounted, to the defined path. It could be defined within the .gitpod.yml.

Describe alternatives you've considered

At the moment I use an external database server and manually copy assets to the workspace

Start by reviewing the .gitpod.yml configuration and how it currently describes workspace resources. Compare the requested Docker-volume or Kubernetes-PVC behavior, including creating, mounting, sharing, and duplicating volumes; done means a persistent volume can be selected and mounted at a defined path across workspaces.