teststeps: Generic support of step driven tests

teststeps: Generic support of step driven tests

In the past, step driven testcases were supported
only by integration testcases. This patch adds generic
support of TestSteps for both integration and performance
testcases. Step driven test were improved to support
modification of existing deployment. As part of
the patch a refactoring of traffic controllers
were performed. Traffic controllers were modified
to support trafficgen-off and trafficgen-pause
modes in all possible ways of trafficgen invocation.

JIRA: VSPERF-362

Change-Id: Ic8b7a9b0e7165f0a15a52279ed0f0952da9fedb8
Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Maryam Tahhan <maryam.tahhan@intel.com>
Reviewed-by: Al Morton <acmorton@att.com>
Reviewed-by: Christian Trautman <ctrautma@redhat.com>
Reviewed-by: Bill Michalowski <bmichalo@redhat.com>
Reviewed-by: Antonio Fischetti <antonio.fischetti@intel.com>
Reviewed-by: Sridhar K. N. Rao <sridhar.rao@spirent.com>