Prop 79: [SIPS-075] Proposal to Replace the Cellar Adaptor in RYBTC

This text proposal is to replace the RYBTC Cellar Adaptor with an improved version called the Legacy Cellar Adaptor. This adaptor will enable RYBTC to cheaply take a position in RYETH. If accepted, a steward update will enable the strategist to add the new adaptor. See the corresponding forum post for more details: https://community.sommelier.finance/t/sips-075-upcoming-proposal-to-replace-the-cellar-adaptor-in-rybtc/1183