fix(logstash): Allow managing "logstash" index
fix(logstash): Allow managing "logstash" index

When data streams are disabled in Logstash's "elasticsearch" output
('data_stream => false'), Logstash falls back to managing "logstash-*"
indices and creates an index template with ILM enabled.
In this process, a write index for the alias "logstash" is created. This
step requires the "manage" privilege on the "logstash" alias.

Fixes #679

deviantony/docker-elk,deviantony/docker-elk