CSIT-992: Add libraries for optimized search

CSIT-992: Add libraries for optimized search

+ Place the libraries into resources/libraries/python/search/.
 + Except OptimizedTrexSearch in TrafficGenerator.py
+ Change traffic generator to support floats for duration and warmup.
+ Remove explicit type conversions where not needed.
+ Add robot keywords to performance_utils.robot
 + for calling the optimized search.
 + for reporting the resulting values.
 + for checking the minimal performance has been reached.
 + for running five second "Traffic should pass with no loss" after the search.
- Add methodology documentation in subsequent Change.
- Add simulator for testing algorithm correctness in a subsequent Change.
- Add tests using the libraries in subsequent Change.

Change-Id: Ia041008382ee4c9a562172099aea794c854d5f2f
Signed-off-by: Vratko Polak <vrpolak@cisco.com>