DOCS-235 - Historical baselines in Cloud SIEM

[jpipkin1]

Purpose of this pull request

This pull request adds a release note and updates the following articles for new baseline behavior in Cloud SIEM rules:

• https://help.sumologic.com/docs/cse/rules/write-first-seen-rule/
• https://help.sumologic.com/docs/cse/rules/write-outlier-rule/
• https://help.sumologic.com/docs/cse/rules/rules-status/

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-235

[jpipkin1]

Thanks for the review, @kimsauce!