logstash: puppetize the main logstash configuration file

Add the pipeline.ecs_compatibility property compared to the manual version existing in the server

Related to T3705

Test Plan

diff origin/production/logstash0.internal.softwareheritage.org current/logstash0.internal.softwareheritage.org
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+ File[/etc/logstash/logstash.yml] =>
   parameters =>
     "content": "#\n# File managed by puppet (profile::logstash). All modificatio...
     "ensure": "file",
     "notify": "Service[logstash]"
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*** End octocatalog-diff on logstash0.internal.softwareheritage.org

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Migrated from D6659 (view on Phabricator)