Merge pull request #1668 in SNORT/snort3 from ~DAVMCPHE/snort3:single_flowCache to...

Merge pull request #1668 in SNORT/snort3 from ~DAVMCPHE/snort3:single_flowCache to master

Squashed commit of the following:

commit 9ba243badce51f88109251156be8efaf97ff1c3c
Author: Devendra Dahiphale <ddahipha@cisco.com>
Date:   Sun Jun 30 03:36:52 2019 -0400

    Flow: make a single flow cache for all the protocols

    flow: refactor flow config object to work with single flow cache concept

    flow: if no 'get_ssn' handler configured then skip processing of the flow

    flow: release session object allocated for a flow when the Flow object is reused and the PktType of the new flow is different from the previous use

    stream: update checks for modified stream config to work with updates to stream config options

    flow: refactor uni list managment into a separate class and instantiate an instance for ip flows and another for all non-ip flows

    snort2lua: Combine proto specific cache options for max_session in one max_flows option