* Add xpack setting deprecations to deprecation API
The deprecated settings showed up in the deprecation log file by
default, but I did not add them to the deprecation API. This commit
fixes that. Now if you use one of the deprecated basic feature
enablement settings, calling _monitoring/deprecations will inform you of
that fact.
* Remove incorrectly backported settings documents
It seems that I backported these docs to the wrong place in #56061,
in #55980, and in #56167. I hope they're in the right place now.
Co-authored-by: debadair <debadair@elastic.co>
691044e67b