tls: add --tls-min-v1.2 CLI switch

For 11.x, the default minimum is TLSv1, so it needs a CLI switch to
change the default to the more secure minimum of TLSv1.2.

PR-URL: https://github.com/nodejs/node/pull/26951


Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>