Move constants to Java files to avoid recompiling Native layer

[RHenigan]

Bug Report

Currently, some of the configurable variables for sdl security are in the java layer (Constrants.java) and some are in the native layer (tlsEngine.cpp). It will be nice if we can put all the configs in the java layer so they are all in one place.
If that is not easy, add good docs in the read me to specify how to modify all configs.

Need to make sure we're not requiring the developer to recompile the c layer