This change reintroduces the system index APIs for Kibana without the
changes made for marking what system indices could be accessed using
these APIs. In essence, this is a partial revert of #53912. The changes
for marking what system indices should be allowed access will be
handled in a separate change.
The APIs introduced here are wrapped versions of the existing REST
endpoints. A new setting is also introduced since the Kibana system
indices' names are allowed to be changed by a user in case multiple
instances of Kibana use the same instance of Elasticsearch.
Relates #52385
Backport of #54858
This commit introduces a module for Kibana that exposes REST APIs that
will be used by Kibana for access to its system indices. These APIs are wrapped
versions of the existing REST endpoints. A new setting is also introduced since
the Kibana system indices' names are allowed to be changed by a user in case
multiple instances of Kibana use the same instance of Elasticsearch.
Additionally, the ThreadContext has been extended to indicate that the use of
system indices may be allowed in a request. This will be built upon in the future
for the protection of system indices.
Backport of #52385
Jay Modi
Ryan Ernst