Deprecate DowngradingConsistencyRetryPolicy
Description
It is generally agreed that DCRP is a misfeature, and should be removed. The basic reasoning is that if an application is okay with the downgraded CL, the request should just be run at that level.
Since DCRP will be removed in 4.0 (see JAVA-1376), we should deprecate it in the 3.x series and encourage users to migrate their code.
Environment
None
Pull Requests
None
