Update tenant inventory collection

Use the OpenStack Identity Service (Keystone) to collect the full list of
tenants in OpenStack installations.
Add migration and model for quotas

* Create cloud_resource_quotas table with STI
* Create CloudResourceQuota and OpenstackResourceQuota model
    - explicitly set tablename for CloudResourceQuota since rails believes that
      the plural of "quota" is "quota"
* Update CloudTenant and EmsCloud with quota relationships

Add migration and model for quotas

Add ems relationship to quotas

Explicitly set table name for cloud quotas

According to Rails, the plural of quota is quota.  But, to stay consistent, the
table name is overridden to be "cloud_resource_quotas".

Add quotas relationship to cloud tenants
Add quota inventory collection
Add attr_accessible to cloud_resource_quota

Allows update_attributes to set type and cloud_tenant_id
Adding cloud_tenant nav bar and feature fixtures

* update page header navbar to include cloud tenant link under "Clouds" header
* add miq_product_feature fixtures for tenant feature and children
* add miq_shortcut fixtures for tenant list
Add cloud tenant routes
Show cloud tenants in ems_cloud textual relationships
Add cloud_tenants to EMS Relationships tree view
Add cloud tenant list view inside ems_cloud
Add cloud tenant list page

* create cloud_tenant_controller with show_list method
* copied availability_zone icon for cloud_tenant icon
  - cloud_tenant needs dedicated icon
* created show_list view for cloud_tenant

NOTE: requires cloud_tenant.png icon ... currently borrowing
availability_zone.png icon
Let cloud_tenant be taggable
Add cloud tenant detail page

* add CloudTenantController#show
* add show and _main views for cloud tenant
* add listnav layouts
* add panel_control route for cloud_tenant
* add summary view helpers
Fix cloud tenants nav bar

Show the active nav and subnav selections when viewing cloud tenants
Add security groups and images to tenant view

* add security groups to listnav, textual summary, and graphical summary
* add miq_templates relationship to cloud_tenant model
* add images (miq_templates) to listnav, textual summary, and graphical summary
Whitespace cleanup in cloud_tenant_controller
Add quotas to cloud tenant view

* show all qoutas in textual summary view for cloud tenant
Fix quota summary display on tenant view

* show "Unlimited" when the quota value is negative

http://docs.openstack.org/user-guide-admin/content/cli_set_quotas.html#cfg_quotas_common
Format quota label name in textual summary

Format the quota label on cloud tenant textual summary page.

Eg.
  quota.service_name = "compute"
  quota.name         = "floating_ips"
  label              = "Compute - Floating Ips"
Rubocop fixes

Applied fixes for some of the rubocop complaints.  However, the rest are
complaints against code that is purposefully breaking style in order to conform
to either similar code in the same class or similar code that implements similar
functionality.
Add tenant column to preprovisioning

Show the tenant column on the pre-provisioning page when provisioning cloud
instances.