Using the feature flag for SPM-3556, add calls (demonstrated below) to all callsites that currently acquire the WT oplog manager, and add calls to the new visibility manager. This connects the "read" side of the new datastructure to other consumers in other modules.

if (gFeatureFlagOplogVisibility) {
  auto* opvis = repl::OplogVisibilityManager::get(opCtx);
  return opvis->getOplogVisibilityTimestamp();
else {
  return getOplogManager()->getOplogReadTimestamp();
}

There are other related calls on the old oplog manager that can also be replaced with their equivalents on the new oplog visibility manager. Notably, this ticket encompasses calls to waitForAllEarlierOplogWritesToBeVisible which is the majority of uses of both the old and new visibility systems.