Improve Fuel Default Disk Partition Scheme

Currently Fuel will use all available Hardware Luns under LVM and Span them across.
Which means that we are coupling OS and Guest traffic.

Normal production deployment is raid 1 hardware mirror for OS and Raid 10 for ephemeral.
This should not be combined into a single logical device by LVM.

Ideal allocation scheme

hardware raid 1 = OS ( you will see this as a single LUN)
option:
Hardware raid 10 = Ephemeral ( you will see this a single LUN)
 or
Bunch of JBODS or RAID 0 LUNs for Ceph and Swift

For Sahara/Savana ideally we want to have the ability to have multiple ephemeral devices and ability to map raw disk partitions to guest virtual drives. But that will require a change to openstack, as you would want to provide more than one ephemeral device to a VM.

The question is much more complicated, then just switch to LUN/Harddisks. We have a lot of possible roles combinations and a lot of possible hardware configurations.
The work on LSI RAID support (https://blueprints.launchpad.net/fuel/+spec/lsi-raid-controllers) should be considered.

Original ticket: https://bugs.launchpad.net/fuel/+bug/1306792