Documenting hypervisor support for nova meters

Support was recently added for HyperV and Vsphere for Nova meters in
ceilometer. However, not all meters are supported by all the
hypervisors. Hence, have added documentation to list the meters and the
hypervisors which provide support for them.

Change-Id: I9c828ffdd8276a487a35f31ba4ba11dcab93964c
Implements: blueprint vmware-vcenter-server
Remove escape character in string format

String format can use escape character '\' to break lines, but it
requires the continuous line not be aligned or the spaces will be
included too. This patch uses parentheses to format string, and
removes the '\'.

Change-Id: I6c007d48d9b99d102c82b4d93ef6f825828e9e20
improve performance of resource-list in sql

simplify the query to retrieve list of resources. it is much simpler
to query against raw Sample data then to join against Resource table.

also, add meter_links param to allow ability to disable link generation of
relate meters.

Change-Id: Ia4ceafc568c4a2e4c8e6b7586511135627b9335e
Closes-Bug: #1264434
Implements: blueprint big-data-sql
Merge "Documenting hypervisor support for nova meters"
Merge "Remove escape character in string format"