dash: parse ProRegTx v3 layout #1132

Part of #1047.

ProRegTx v3 has a different layout after nOperatorReward: nested netInfo (ExtAddr), payouts[], shares[], joinSigs[], nEarlyPeriodBlocks, nEarlyPenalty, then inputsHash. It has no scriptPayout, and Evo platformNodeID comes without port fields. Core src/evo/providertx.h:162-226.