Segsignal compatible UASF

Segsignal compatible UASF

fixup! Improve api to estimatesmartfee

Convert named argument from nblocks to conf_target

in estimatesmartfee and estimaterawfee.  Also reuse existing bounds checking.

fixup! Add a discard_rate

Add a discard_rate

Any change output which would be dust at the discard_rate you are
willing to discard completely and add to fee (as well as continuing to
pay the fee that would have been needed for creating the change).

fixup! fixup! Refactor to use CoinControl in GetMinimumFee and FeeBumper

Properly bound check conf_target in wallet RPC calls

fixup! Refactor to use CoinControl in GetMinimumFee and FeeBumper

Properly bound check conf_target in wallet RPC calls