Orchestra should make storage as generic as possible

Ensemble must be able to depend on generic system properties in order to ensure formulas are compatible across many different machine types. In the cloud, we have the luxury of instance types (m1.small, t1.micro), each with pre-defined properties. For example, an m1.small will always have an extra storage device (/dev/xvda1) mounted at /mnt at boot. Formulas that require a storage device can reliably derive whats available via the instance type.

This is not the case on hardware, and one node may have /dev/sdb and /dev/sdc free and avaiable while the node beside it has something different. In interest of making this generic across nodes, Orchestra installations should be preseeded to create an LVM2 volume group across all extra storage devices and a single logical volume that represents the all of the additional storage space. Then, every formula deployed via orchestra can count on something like /dev/orchestravg/orchestralv.