Replace inline schema urls with reference to single piece of data

Change-Id: Ibfad5e20cc60f553e44780ee8ef4f2fee6f0732c
Region support

When there are multiple regions shared with one keystone, we should be
able to specify the region for the endpoint.

Change-Id: I18bb2c7630d0b1927969f6e06f30998644902020
Implements: blueprint region-support
Split ContinuousScenarioRunner to constant and constant duration

* When 'type' in scenario config is 'constant', then
  use ConstantScenarioRunner.
* When 'type' in scenario config is 'constant_for_duration',
  then use ConstantForDurationScenarioRunner.
* Sample task configs renamed from 'continuous' to 'constant'.
* Renamed continous.py to constant.py.
* Error to specify 'continuous' for 'type' in scenario config.
* Error to specify 'times' and 'duration' in same config.
* Error to omit 'type' from scenario config.
* Error to omit 'duration' when 'type' is constant_for_duration.
* Improved unit tests to include timeout failure mode cases.

bp benchmark-split-continuous-runner
Change-Id: Idb83f5be538bce5740c7cb6211364caaf2d53b7d
Add number and file validators

 * number: Check a numeric argument specifying min, max. Optionally
           require input to be integer.
 * file_exists: Check that a file exists and can be opened

 These validators are used in the runcommand in instance benchmark
 (patch pending)

Change-Id: Ia12e95b3661c97ae6f4c54caf44fdf33b72aa736
Create vm benchmark module

Move the run command in instance benchmark out of the nova module into
its own module (vm). Functionality is then split into a scenario module
and a utils module, following the structure of the other benchmarks.

Tests are also refactored.

Change-Id: Ida26b5047b8e76f72e34c2aab9b8ab94f46bbad6