Consider adding "since" attribute on DeprecatedConfigurationProperty

[snicoll]

When deprecating a configuration property, it is not always obvious when we did that. We could mention that in the Javadoc of the getter but the documentation for the property is set on the field so it's not natural for us to repeat it there.

Perhaps a since extra attribute that we'd use solely for the purpose of tracking could be an idea? Or perhaps we could generate that information in the metadata as well in case that's useful to users?

See #20812 (comment)