This commit removes the fallback for SSL settings. While this may be
seen as a non user friendly change, the intention behind this change
is to simplify the reasoning needed to understand what is actually
being used for a given SSL configuration. Each configuration now needs
to be explicitly specified as there is no global configuration or
fallback to some other configuration.
Closes#29797
Moves `x-pack/qa/sql/*` into `x-pack/plugin/sql/qa` to make it simpler
to run all of the sql tests. This lines up with how newer projects like
cross cluster replication are testing themselves.