Doc: Coordinate plan to publish logstash-integration-snmp docs to LSR and VPR

[karenzone]

Related: https://github.com/logstash-plugins/logstash-integration-snmp/pull/1

Coordinate plan to publish logstash-integration-snmp docs, with regard to:

• [x] Timing. WHEN should this doc be published in the Logstash Reference and the Logstash Versioned Plugin Reference?
• [x] Fixes. Resolve current issues in source docs that will cause docs-ci to fail. These issues should be resolved before we publish to rubygems.org for the first time.
• [x] Iteration. Hooking up docs for new integration plugins is an iterative process. If not, remediation is a time-consuming pain.

Next steps: Publishing plugin docs

• [x] Remove plugin from docgen skiplist (VPR)
• [x] Remove plugin from docgen skiplist (LSR):
• [x] Add plugin to integration plugin index (LSR)

[karenzone]

Work in progress: https://github.com/logstash-plugins/logstash-integration-snmp/pull/1

[karenzone]

Completed