This fixes two issues:
1. This fully removes the xopts parameter which for Shared and Single concurrency would prevent outputs from receiving their parameters
2. This cleans up the injection of the OutputDelegatorStrategyRegistry.
This also bumps the plugin api version to 2.1.12
Fixes#5794
Purpose:
* manage releases through a minimum number of rake tasks
* simplify building of snapshot builds
* create staged artifacts, candidates for releases, that required no changes to become releases
* this means the snapshot release process will not involve publishing gems, therefore:
* the gem artifacts should only be published to rubygems as a final artifact, at the time of GA
Changes:
* release artifacts no longer depend on gems of core components
* all core components are used locally AS-IS to minimize code changes between snapshot, RC and GA
* `versions.yml` describes the versions of all logstash parts and package
* `rake version:set[version]` manage the yaml file and push the changes to the gemspecs/version.rb files
* `rake version:set_plugin_api[version]` manage the yaml file and push the changes to the gemspecs/version.rb files
* `rake artifact:all` generates SNAPSHOT artifacts: tar.gz, zip, rpm, deb
* `RELEASE=1 rake artifact:all` creates release candidate artifacts + 4 gems: logstash-core, logstash-core-event, logstash-core-event-java and logstash-core-plugin-api
implements #5416 and #5414Fixes#5460
