Added base classes for Load Tests and profiler

[OpenStack Infra]

https://review.openstack.org/123967
commit cabab8ab7b3b0fdd3f0612d2bccbb31f53eb323c
Author: Kamil Sambor <email address hidden>
Date: Thu Sep 25 09:35:50 2014 +0200

    Added base classes for Load Tests and profiler

    * added nailgun profiler
    * added base clases for load test
    * added integration tests

    Tests are run only when teh are set in settings
    (PERFORMANCE_PROFILING_TESTS) is set on True, also profiler runs
    only when this variable is set. All artifacts from profiler are
    writen in /tmp/nailgun_load_tests/results/, directory can be
    changed in settings.yaml.

    DocImpact
    Change-Id: I2be46c2a0a51544b12a1d9f2a840d4edc3ede2c4
    Blueprint: 100-nodes-support