yescrypt Catena-like features

Current:
Client-side computation of almost final yescrypt hashes (server relief)
in a way allowing for a straightforward extension of SCRAM (RFC 5802)
Planned:
Hash upgrades to higher cost settings without knowledge of passwords
Can be defined and implemented without breaking compatibility with current yescrypt
Will support over 60% area-time efficiency, as opposed to Catena's over 33%
Optional full or partial cache timing side-channel resistance
This is a trade-off since it weakens TMTO resistance and removes dependency on memory latency (but yescrypt's multiplication latency hardening will help)