Updates instructions on how to import models (elastic#1535)

Updates instructions on how to import models

This update will point directly to the eland API which has an example and full list of supported models. This is the right place to document limitations as this is where it's implemented.

Author: joshdevins

docs/en/stack/ml/df-analytics/ml-trained-models.asciidoc

@@ -143,15 +143,8 @@ Elasticsearch cluster, for example by adding nodes.
 == Importing an external model to the {stack}
 
 It is possible to import a model to your {es} cluster even if the model is not
-trained by Elastic {dfanalytics}.
-
-You can find an example of training a model, then importing it to {es} with
-`eland` in the
-https://eland.readthedocs.io/en/latest/examples/introduction_to_eland_webinar.html#Machine-Learning-Demo[eland machine learning demo].
-The example uses Python to train, save and import the model. However, you can
-use any client as long as the model conforms to the 
-https://github.com/elastic/ml-json-schemas[schema].
-
-// This blog post is a step by step description of how to create a random forest
-// classifier {ml} model outside of {es} by using Python, load it into {es},
-// then operationalize it with ingest pipelines.
+trained by Elastic {dfanalytics}. https://eland.readthedocs.io/[Eland] supports
+https://www.elastic.co/guide/en/elasticsearch/client/eland/current/machine-learning.html[importing models]
+directly through its APIs. Please refer to the latest
+https://eland.readthedocs.io/[Eland documentation] for more information
+on supported model types and other details of using Eland to import models with.