Allow default zone description to be changed

Removed the section of code that was blocking the default zone description
from being changed. Displayed the zone description when add/edit a ems.

https://bugzilla.redhat.com/show_bug.cgi?id=1098305
Rewritten vm_infra view to HAML
Rewritten vm_or_template view to HAML
Rewritten vm_vdi view to HAML
Rewritten vm_cloud view to HAML
Config partial refactored and rewritten to HAML

I haven't found any use case of @display == "prop" and it also generated invalid HTML, so I've removed it.
Rewritten vm_common partials to HAML
Rewritten VM view to HAML

Some obsolete files were removed
Disable revert to / remove snapshot button if no snapshots exist

https://bugzilla.redhat.com/show_bug.cgi?id=1096746
Update specs for ApplicationHelper

build_toolbar_disable_button() method now returns (error) message
in case no snapshots for VM exist. The routine now returns false
only in case the VM does have snapshots.

https://bugzilla.redhat.com/show_bug.cgi?id=1096746
Enable storage deletion from provider's storage list view

https://bugzilla.redhat.com/show_bug.cgi?id=1140483
Rewritten repository view to HAML
Removed attr_accessor in order for the methods to be called

The following methods-
:v_derived_storage_used
:min_v_derived_storage_used
:max_v_derived_storage_used

that populate the trending data for datastore were not being called
earlier due to attr_accessor being specified.

https://bugzilla.redhat.com/show_bug.cgi?id=1089625
Fix for External Auth

External Authentication broke with the move of user
authentication code as a service. We need to pass
the request env to look/honor Apache based
authentication.
Merge pull request #750 from skateman/view-vms-to-haml

Rewritten views/vm* to HAML
Remove unused action check_redirect.
Remove unused action toggle_debugws.
Replace call to removed ie8_safe_redirect
Rewritten dashboard view to HAML
Merge pull request #790 from abellotti/external_auth_fix

Fix for External Auth