Check_MK Werk 6118: Add a analyze configuration rule for flexible and plain email notifications

ID: 6118 Title: Add a analyze configuration rule for flexible and plain email notifications Component: Multisite Level: 1 Class: New feature Version: 1.6.0i1 A deprecation warning will be shown if rulebased notifications are deactivated since flexible and plain email notifications are considered deprecated and will be removed in the next release.