This adds config options for unified limits quotas that allow
admin/operators to specify which resources they will require or ignore
to have unified limits set in Keystone.
The options are only used when ``[quota]driver`` is set to
``UnifiedLimitsDriver``.
When the resource strategy is set to 'require' (the default), the
resource list will represent the resources that are required to have a
registered limit set in Keystone.
When the resource strategy is set to 'ignore', the resource list will
represent the resources that will be ignored for quota enforcement if
they do not have a registered limit set in Keystone.
Related to blueprint unified-limits-nova-unset-limits
Change-Id: Icb08fadbdbf9c1bf354c3091f05edce80ebf68c3
melanie witt
fd5b692905