Refactor Burn AnteHandler and deprecate Seigniorage Reward Policy

[dfunk]

@godoal

The solution contains three parts:

1. Parameter Proposal to set the seigniorage reward policy back to 0, so we stop remint immediately
2. Text proposal to instruct validators to increase the gas fees 5x. If memory serves they need to change a line in their nodes with the new values and restart.

A proposal for this has been created here: [Proposal] Deprecate Seigniorage Reward Policy and Increase Gas Fees by 5x