OAK-1031: SegmentMK: Fewer segment lookups

Move functionality from Template to SegmentNodeState to better leverage the Record base class

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1527635 13f79535-47bb-0310-9956-ffa450edef68
OAK-1031: SegmentMK: Fewer segment lookups

Reduce the default size of the record cache to see if that avoids the OOMEs in CI

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1527636 13f79535-47bb-0310-9956-ffa450edef68