Modified validation script for tracing to support CI

Modified validation script for tracing to support CI

- Changed default Jaeger ports to 16686 for use with basic
kubernetes port-forward and CI scripts
- Added CLI to validate script to disable istio service check
by default. This requires at least a single http request
to istio-ingress after Jaeger deployment. It can be enabled
with 'python validate.py -s'. Port and IP address for Jaeger
can optionally be specified with '-ip' and '-port' options
- Modified tracing doc to add k8s port-forward example in addition
to k8s expose

Change-Id: I10fb4d3cccfa50370d44ed7446f67a49c538bba9
Signed-off-by: Eddie Arrage <eddie.arrage@huawei.com>