* Refactor SSL setup in X-Pack
This commit makes some internal changes to the way SSL configuration
works in X-Pack. This is in preparation for replacing the X-PackSSL
configuration with "libs/ssl-config" instead.
* Adds a new class to x-pack core that can loads
SslConfiguration objects (as defined in the ssl-config library),
from standard Elasticsearch Settings objects.
This class supports the semantics that are used for "xpack.*.ssl.*"
settings.
* Refactors the internals of SSLConfigurationSettings to reduce the
number of constants and the duplication of code between them
* Address feedback
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
a81f0b4f29