Update comment in yaml to indicate size limit for the following vars -
stream.reassembly.toserver-chunk-size and stream.reassembly.toclient-chunk-size
Fix PmqSetup calls in Liveswap thread init. Func was out of sync with normal thread init.
detection engine: consolidate thread setup

DetectEngineThreadCtxInit and DetectEngineThreadCtxInitForLiveRuleSwap did
pretty much the same thing, except for a counters registration. As can be
predicted with code duplication like this, things got out of sync. To make
sure this doesn't happen again, I created a helper function that does the
heavy lifting in this function.
Use define instead of magic number for pmq's per detect thread
Minor reshuffling of Signature struct.