Provide missing hover hints for instance:<type> meters

Fixes bug 1243241

Previously, the Metric dropdown list on the Stats tab of the admin/
Resource Usage panel had hover hints with a short description of each
meter, except for the instance:<type> meters which were missing.

Now, we construct the hover hints list using the current set of flavor
names as reported by nova.

Change-Id: Ieb64ee1eec43fae6036a3a97e86907b9fcc201e1
(cherry picked from commit 386d5865689aeb344182133790bdcb192789b3d2)
Change "Tenant" to "Project"

Fixing inconsistency verbose_name of some columns in
'Resource Usage' panel.

Change-Id: I55969f6fa67be1758a2c03b06237a9a66fe7ef40
Fixes: bug #1250942
(cherry picked from commit a4a3cfbca28bfc2a650dd45202dfca0f6617f52e)
translate text: "subnet"/"subnet details"

When trying to create or update a subnet from the Networks
details page, the tab titles 'Subnet' and 'Subnet details'
are not showing as translated. This patch add the missing
underscore.

Change-Id: I48cd47e7ead3717d96e4808f41bf876a567c8052
Closes-Bug: #1254026
(cherry picked from commit 599c2135e5dfdcf88324faf1a8336a252db72d2f)
Merge "Change "Tenant" to "Project"" into stable/havana
Merge "Provide missing hover hints for instance:<type> meters" into stable/havana