DOCS-25 - Threat intelligence - GA

[jpipkin1]

Purpose of this pull request

This pull request removes the "Threat Intelligence Indicators" beta article and replaces it with this new section at GA:
https://help.sumologic.com/docs/platform-services/threat-intelligence/

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)

DOCS-25

(Migrated from Asana ticket: "Document Next Gen Threat Intelligence - GA")