remove ruby execution engine

[kaisecheng]

Fixed: #11236

This PR removes the Ruby Execution Engine
The Java Execution Engine has been the default engine since Logstash 7.0, and is capable of using plugins written in either Ruby or Java; removing the Ruby Execution Engine will not affect our ability to run existing pipelines, but will greatly reduce the surface area of all features and fixes within the engine(s). We will no longer need to target two engines simultaneously.

Ruby execution engine uses Treetop to parse Logstash config files and convert them to executable code which is being referenced by Java pipeline, so Treetop stays in the project.

• remove Logstash::Pipeline
• rewrite test cases which depend on ruby pipeline
• remove logstash/event, Logstash::SignalEvent
• remove Engine.Ruby on java side
• remove config pipeline.java_execution

This PR will split into three smaller to feature branch for review
#12496 remove Logstash::Pipeline, Engine.Ruby, rewrite test cases
#12505 remove Logstash::SignalEvent
#12506 remove config pipeline.java_execution

A follow up will be removing logstash/pipeline in logstash-devutils

• clean up devutils remove logstash/pipeline logstash-devutils#89
• check tier 1 plugins reference
• clean up input-redis remove ruby pipeline dependency logstash-plugins/logstash-input-redis#84
• check tier 2 plugins reference

[kaisecheng]

move the PR to #12517