Enable SCM Ratis by default for new clusters only

HDDS-5740 (Enable ratis by default for SCM) has been reverted, since it will cause the upgrade framework to fail SCM startup on upgraded clusters where SCM HA/SCM Ratis is not yet finalized. Since it is always possible and supported to upgrade an older version of Ozone from before the SCM HA layout feature to a version of Ozone with the SCM HA layout feature, this option can never be the default for upgraded clusters.

However, for new clusters, even those that do not explicitly configure HA, it is best to use Ratis by default for SCM as noted in HDDS-5740 so that a non-HA SCM setup can easily be bootstrapped to an HA setup later.

This Jira is to make the config key ozone.scm.ratis.enable default to true for new installations, and false for for existing non-HA/non-Ratis installations.