Add user documentation for opt-in buffer identification mechanism

This is important information. Having that inside user documentation would be helpful. I think we should crate an issue to put this into the user documentation.

_Originally posted by @paulquiring in https://github.com/eclipse-score/baselibs/pull/174#discussion_r3586445596_

Start by reading the opt-in buffer identification discussion in pull request #174, then locate the repository's existing user documentation structure and the mechanism described there. Add documentation explaining the mechanism and its opt-in behavior. Done means users can find and understand this information in the user documentation.

Written by the indexing model from the issue text.