`bw` is not part of `additionalKeyValues()`

Code that landed for #52 (closed) contains (among others):

        long bw = -1L;
        if (relayLine.additionalKeyValues().get("bw") != null) {
          bw = Long.parseLong(
              relayLine.additionalKeyValues().get("bw"));
          opWriter.processRequest(bwGauge, nodeId, nick, null, rt, bw);
        } else {
          logger.warn("`bw` Key is null, this should never happen.");
        }
        preparedStatement.setLong(2, relayLine.bw());

The if-else clause is wrong in assuming bw is part of additionalKeyValzes() as the preparedStatement.setLong() call shows. One can see that as well in the metrics library code in BandwidthFileImpl.java:

      switch (key) {
        case "node_id":
          nodeId = value;
          break;
        case "master_key_ed25519":
          masterKeyEd25519 = value;
          break;
        case "bw":
          try {
            bw = Integer.parseInt(value);
          } catch (NumberFormatException e) {
            throw new DescriptorParseException(String.format(
                "Unable to parse bw '%s' in line '%s'.", value, line), e);
          }
          break;
        default:
          additionalKeyValues.put(key, value);