Doc: Logstash 7.17.27 release docs

[karenzone]

Logstash release manager: @kaisecheng
Logstash tech writer: @karenzone
Docs release manager: @KOTungseth

Logstash release docs

• Release notes: Release notes for 7.17.27 #16878
  • Add link to docs release issue: https://github.com/elastic/dev/issues/2955
• Update plugin docs: updated docs for 7.17 logstash-docs#1785