HBD stabilizer proposal

Please review my earlier request for comments post on this topic. The details of the proposal are primarily contained within that post.

Per feedback from @marki99, I have made one adjustment: We will table LOW (situation where HBD is below 1 USD) for now. Instead, any time HBD can not be sold for >1 USD, the HBD will just be sent back to the DAO. There are various complications brought up with the sliding peg when the debt limit is reached (resulting in a "fair value" of HBD below 1 USD), and overall, as @marki99 points out, under-peg situations are already reasonably well-handled by the structure and incentives. It is the upper peg which is the most serious deficiency, so it is being prioritized. We may revisit below-peg situations later.

The proposal will pay out to, and the stabilization process will occur within, the account @hbdstabilizer.

Donations (including beneficiary) may be made to that account, and will be used to stabilize HBD upon receipt (if needed) and then the proceeds donated to the DAO.

The initial proposal is being submitted to run for an initial period of 90 days. If conditions dictate, we may submit a revised proposal sooner (for example with a higher budget). If not, then the situation will be reevaluated after 90 days and a renewal may be submitted at that time.

Proposal number is 158

Link to hivesigner to approve

100% of rewards will be donated to @hbdstabilizer