Implement Send support (embit)

[macgyver13]

Description

added the sender-side logic for BIP-352 silent payments, this lets us generate P2TR (Taproot) destination addresses.
this PR is built on top of keith's SP address generation PR diybitcoinhardware/embit#64

Purpose

No response

Repository: diybitcoinhardware/embit#96

Development Team:
Lead: @notTanveer