Add tomcat-benchmark

This module contains a servlet benchmark from FrameworkBenchmarks.
See README for usage.

Signed-off-by: Asias He <asias@cloudius-systems.com>
Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
tomcat-benchmark: use servlet.war artifact from cloudis-systems/FramewroksBenchmark release

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>