[ADD] Support Stablecoin for Savers
A dev has motioned to open up Savers vaults to stablecoin pools. A thread containing the pros/cons and viewpoints of various community members can be found on the Dev Discord (in #economic-design, "Stables for Savers PoL" https://discord.com/channels/838986635756044328/1133907652716536001).
Their original message was as follows:
This is a temperature check on enabling Savers + PoL for stablecoin pools (all pools listed as "anchor", which are used for the price feed for TOR)
Recently Treasury has realised it owns the vast majority of stable dual-LP due it to setting and forgetting, other dual-LPs may have pulled to protect their capital, Treasury LP is an LP of last resort and are not withdrawing
Good:
* Stablecoin Savers may be a big feature! Stable income on a stable asset. Noting Anchor+UST was such a huge vehicle
Bad:
* Stablecoin Savers may be too popular, causing a huge PoL position in a stable asset (bad in bear markets)
Mitigation:
Suggest to have anchorPoolsLiquidityMaxBasisPoints = 3333 which means TC will stop adding liquidity into Anchor pools when they hit 33% of the total TC TVL (so only 1/3rd allowed to be in stables)
Nodes were asked to provide a dissenting opinion on the matter, noting that the change was non-contentious amongst devs (https://discord.com/channels/838986635756044328/839001804812451873/1134361936755171369). After 72 hours, the measure was assumed to have passed without dissent.
The technical implementation requires some way of distinguishing stable pools from all others. Lending has this facility in the form of the TOR anchor pools mimir. As such, this should be used to determine additional eligibility for Savers vaults. A different issue/PR shall be opened to expand PoL eligibility.