Resolved JERSEY-2259: major test framework revamp.

- Introduced concept of container deployment contexts (inspired by AppDescriptor from Jersey 1.x).
- TestContainerFactory.create signature changed to use DeploymentContext.
- Added support for ServletDeploymentContext via GrizzlyWebTestContainerFactory.
- Fixed all locations where JerseyTest.getClient has been overridden.
- Protected JerseyTest.getClient method refactored and made private.
- Removed support for specifying test container factory as one of the application providers.
- Removed protected JerseyTest.setTestContainerFactory method that was not working anyway.

Change-Id: Ia72ffd4d826541bbef403407b0570b20aa19b27a
Signed-off-by: Marek Potociar <marek.potociar@oracle.com>