[v2]: Investigate possibility to use Block PVs from other storage providers

[WanzenBug]

This idea came up during development of V2: What if the satellite could use other storage provider's "block volumes".

A user could specify some kind of PVC template, which would get mounted as volumeDevices: on the satellite Pod. Configuration of the storage pool then on this volume device, without the user having to manually prepare some raw /dev/... devices.