TIP-93 part 1: tBTC mint fee options

Following extensive deliberation by Threshold Treasury committee and then the community (see Forum discussion in link below), this is the first of 4 snapshots that cover the facets to be decided (mint fee, redeem fee, Treasury committee authorization, 30-day delay for fee changes), while avoiding inevitable "split votes" by trying to combine them.

First two votes are weighted votes, which allow voters to express support for more than one option and specify how much they support each of them (explanation here: https://docs.snapshot.box/user-guides/proposals/voting-types#weighted-voting).