Today Elasticsearch allows default settings to be used only if the
actual setting is not set. These settings are trappy, and the complexity
invites bugs. This commit removes support for default settings with the
exception of default.path.data, default.path.conf, and default.path.logs
which are maintainted to support packaging. A follow-up will remove
support for these as well.
Relates #24093
Fix the `Dockerfile` example in the `Customizing image` third configuration
method by adding the missing RUN instruction.
Originally reported by Shankar Vasudevan (@vshank77).
Relates #21973
The reference for the jvm.options docs recently changed from
es-java-opts to jvm-options. This commit fixes a broken reference that
arose as a result of this change.