Optimize thread safe code and replace the synchronized class "StringBuffer" by an unsynchronized one "StringBuilder". (#2704)

fix issue with assertion in HystrixStreamTests, polish diamond operator and follow class field naming convention (#2703)

* fix assertion check

* polish: replace the type specification in this constructor call with the diamond operator ("<>"),
make EUREKA_PACKAGES final to avoid issue "static non-final field names should comply with a naming convention"

* Remove invalid import

* Remove invalid line

* Move Ribbon to its own module. Fixes #2299