Doc: Validate SSL settings removals from Logstash plugin docs

[karenzone]

In the absence of docs validation in the logstash-plugins org, manual validation is required.
Related:

• Validate doc changes (asciidoc formatting, cross-document links) for plugin doc source docs-tools#42
• https://github.com/elastic/ingest-dev/issues/4776
• Create infrastructure for testing plugin docs for a single plugin docs-tools#19
• Add enhanced CI to capture common doc problems docs-tools#84

Pattern to use for removals (#16717)

• Mark deprecated SSL settings as obsolete logstash-plugins/logstash-output-http#147

Plugins with SSL settings removed:

• logstash-input-beats
• Remove deprecated ssl setting logstash-plugins/logstash-input-elastic_serverless_forwarder#11
• Remove deprecated SSL settings and simplify SSL configuration logstash-plugins/logstash-input-elasticsearch#213
• Remove deprecated SSL settings logstash-plugins/logstash-input-http#182
• Mark previously deprecated SSL settings as obsolete logstash-plugins/logstash-input-http_poller#149
• Mark deprecated SSL settings as obsolete logstash-plugins/logstash-input-tcp#228
• Mark previously deprecated SSL settings as obsolete logstash-plugins/logstash-filter-elasticsearch#183
• Mark deprecated SSL settings as obsolete logstash-plugins/logstash-filter-http#54
• Mark previously deprecated SSL settings as obsolete logstash-plugins/logstash-output-elasticsearch#1197
• Mark deprecated SSL settings as obsolete logstash-plugins/logstash-output-http#147
• Mark deprecated SSL settings as obsolete logstash-plugins/logstash-output-tcp#58

High priority: Must be completed before FF.