Remove legacy store adapters & fix prune of stake pool & epoch settings #1737

All 634 tests pass in 5m 12s

    3 files ±0   16 suites ±0 5m 12s ⏱️ - 1m 31s
634 tests ±0 634 ✔️ +7 0 💤 ±0 0 ❌ - 7
672 runs ±0 672 ✔️ +7 0 💤 ±0 0 ❌ - 7

Results for commit d31de78. ± Comparison against earlier commit cc17d90.