`DROP_WITH_PURGE_ENABLED` configuration is not present in the documentation

[jbonofre]

The DROP_WITH_PURGE_ENABLED configuration is not present in the documentation, and the users don't know this configuration exists and what is the purpose.

[MonkeyCanCode]

@jbonofre here is the PR for closing this gap: #2898.

There appears to be a lot more undocumented configurations. Those are now all captured with PR above.

[jbonofre]

@MonkeyCanCode I noted other configurations that should be documented (I found these while working on the UI and demo). I will create follow up issues/PRs.