Ports #7925 #8365 core to parent_select plugin

Ports #7925 and #8365 from core strategies to parent_select plugin.

PR #7925 adds go_direct support to peering_ring strategies.
PR #8365 refactors strategy consistent hashing to fix a bug.

They both essentially completely rewrite the strategy consistent
hashing, so it was safer and easier to port them both at the same
time.

Author: rob05c