message: [RPC] Return ProgPow epoch also if no miningaddress is set
  in `getblocktemplate` rpc.
diff: @@ -756,25 +756,21 @@ static UniValue getblocktemplate_impl(const std::string &strMode, const UniValue
  result.pushKV("mining_disabled", (!CheckConsecutivePoW(*pblock , pindexPrev))? true : false );
  if constexpr (nPoWType == CBlockHeader::PROGPOW_BLOCK) { // if (pblock->IsProgPow()) {
  + result.pushKV("pprpcepoch", Params().GetProgPowEpochNumber(pblock->nHeight));
  + auto nextEpoch = Params().GetProgPowNextEpoch(pblock->nHeight);
  + result.pushKV("pprpcnextepoch", nextEpoch.first);
  + result.pushKV("pprpcnextepochheight", nextEpoch.second);
  std::string address = gArgs.GetArg("-miningaddress", "");
  if (IsValidDestinationString(address)) {
  static std::string lastheader = "";
  if (mapProgPowTemplates.count(lastheader)) {
  if (pblock->nTime - 60 < mapProgPowTemplates.at(lastheader).nTime) {
  result.pushKV("pprpcheader", lastheader);
  - result.pushKV("pprpcepoch", Params().GetProgPowEpochNumber(pblock->nHeight));
  - auto nextEpoch = Params().GetProgPowNextEpoch(pblock->nHeight);
  - result.pushKV("pprpcnextepoch", nextEpoch.first);
  - result.pushKV("pprpcnextepochheight", nextEpoch.second);
  return result;
  }
  }
  result.pushKV("pprpcheader", pblock->GetProgPowHeaderHash().GetHex());
  - result.pushKV("pprpcepoch", Params().GetProgPowEpochNumber(pblock->nHeight));
  - auto nextEpoch = Params().GetProgPowNextEpoch(pblock->nHeight);
  - result.pushKV("pprpcnextepoch", nextEpoch.first);
  - result.pushKV("pprpcnextepochheight", nextEpoch.second);
  mapProgPowTemplates[pblock->GetProgPowHeaderHash().GetHex()] = *pblock;
  lastheader = pblock->GetProgPowHeaderHash().GetHex();
  }
  