Doc: Create repeatable examples for deleted SSL options in plugin options and breaking changes

[karenzone]

At 9.0.0, we'll be removing deprecated SSL settings from some plugins. We need to be consistent in how we document these changes in both the plugin docs and in breaking changes.

Sample: Settings removal in plugin doc

• PR: Mark deprecated SSL settings as obsolete logstash-plugins/logstash-output-http#147
• Merged content: https://www.elastic.co/guide/en/logstash/master/plugins-outputs-http.html#plugins-outputs-http-options
  • Note at top of configuration options section: https://www.elastic.co/guide/en/logstash/master/plugins-outputs-http.html#plugins-outputs-http-options
  • New section for obsolete config options: https://www.elastic.co/guide/en/logstash/master/plugins-outputs-http.html#plugins-outputs-http-obsolete-options

Sample: Settings removal in Logstash breaking changes

• PR: Add SSL Breaking changes for logstash-output-http to breaking changes… #16701
• Merged content: https://www.elastic.co/guide/en/logstash/master/breaking-changes.html#ssl-settings-9.0

[karenzone]

Samples moved to the issue description to make them easier to find.