Increase Proposal Rejection Cost

For visibility (if this proposal is accepted), adding link to suggestion to change Reject Cost to Spam Reject Cost and get spam identified (>50% of votes) by a check box Is Spam (and cli opt --is-spam which defaults to false) in every proposal (or Is Spam button, I think similar was suggested by @Kyle_Langham).

  • no cost of good-faith rejected proposal so encouraging serious proposers
  • minimal administration overhead for governance - will be manageable also with SNS