Benchmark HashPSQ

- lookup performacne 3x slower than HashMap, 10% slower than Map
- minView 3x faster than GHC_PSQ
- lookup 1.15x faster than GHC_PSQ
- insert of non-existent keys 3x faster than GHC_PSQ
- insert of existent keys 1.17x faster than GHC_PSQ
WIP: implement 'alter' for 'HashPSQ'