Some azurerm resources store resource_group_name in lowercase only.
Other store resource_group_name using lower and upper case.
Ensure that all test cases use capitalisation in resource_group_name
to find errors in diffs due to capitalisation.
Some resource_group_name were refactored to match naming scheme
across the azurerm tests.
This resource is the first which makes use of the new Riviera library
(at https://github.com/jen20/riviera), so there is some additional set
up work to add the provider to the client which gets passed among
resources.