Improve documentation about OpenStack Storage nodes and rolls

[Meg McRoberts]

Need to improve information about Storaghe
- Improve architecural info in http://docs.mirantis.com/openstack/fuel/fuel-5.0/reference-architecture.html#storage-architecture
- Add a chapter to the Planning Guide about "Designing Storage for your Environment"
- Improve Terminology articles about Swift, Cinder, Ceph, etc
- Add information to the Operations Guide about administering and troubleshooting your Storage roles/nodes
- Add information to the Operations Guide about measuring and improving the performance of your Storage roles/nodes
- Be sure that adequate supporting information is available for filling in the Storage-related configuration screens:
  - http://docs.mirantis.com/openstack/fuel/fuel-5.0/user-guide.html#storage-background-for-cinder-and-glance
  - http://docs.mirantis.com/openstack/fuel/fuel-5.0/user-guide.html#assign-a-role-or-roles-to-each-node-server
  - http://docs.mirantis.com/openstack/fuel/fuel-5.0/user-guide.html#storage

The information needs to be complete, although it can link to Community docs for details as appropriate

[Meg McRoberts (dreidellhasa)]

From: Denis Ipatov <email address hidden>

Part 'Storage nodes' was described twice

http://docs.mirantis.com/openstack/fuel/fuel-5.0/reference-architecture.html#storage-nodes

[Meg McRoberts (dreidellhasa)]

https://review.openstack.org/#/c/98313/ to fix the suplicate "Storage nodes" issue.