v2.3.0.4

CORE: Fix a crash in SIGMA verification code that could be triggered in some (relatively rare) instances
RPC: Hide various "hidden" developer RPC commands from the autocomplete
RPC: Introduce a new command "repairwitnessaddress" that can be used to repair a wallet if the witness key for a witness address is not available while wallet is locked (which is required for witnessing)
RPC: Extend "validateaddress" command to give more information for witness addresses
CORE: Minor improvement when renewing witness accounts; check for and repair any instances of missing witness key when doing a renewal