Adds a templated ILM policy with a 3 day or 50 gb rollover and a 3 day retention period by default.
The retention period checks the value set in xpack.monitoring.history.duration and uses that for
the retention period if it is present. Depending on which default it uses, the _meta field is updated
with the reasoning for picking the default retention value.

Co-authored-by: Lee Hinman <dakrone@users.noreply.github.com>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
# Conflicts:
#	x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/template/LifecyclePolicyConfig.java
#	x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlNativeIntegTestCase.java