dominicrume/cantor8_kya_rails: step-1-mandate/daml/KyaMandate.daml

Daml contract source - dominicrume/cantor8_kya_rails/step-1-mandate/daml/KyaMandate.daml ```daml -- KyaMandate: extends the Cantor8 hackathon starter Mandate.daml (credit: Cantor8 toolkit) -- Additions for KYA Rails: counterparty allow-list, charge memo for the audit trail. -- The cap is enforced HE