[8.15] [8.15 & Serverless] Update the Security Timeline Documentation in accordance with new Unified Timeline changes (backport #5505)

[mergify]

Fixes #5341

8.15 previews

• Investigate in Timeline - Made several changes to this page:

  • Revised section about event renderers
  • Wrote a brief explanation of how to add and remove fields from the table
  • Updated the list of actions that users can take from Timeline
  • Updated various screenshots

• Refreshed screenshots and some instructions on the following pages:

  • About Timeline templates | Create a Timeline template
  • Create runtime fields
  • Launch Timeline from investigation guides
  • Timeline schema

Serverless previews

Made duplicate changes in the following places:

• Investigate in Timeline
• About Timeline templates | Create a Timeline template
• Create runtime fields
• Launch Timeline from investigation guides
• Timeline schema

  ---

  This is an automatic backport of pull request [8.15 & Serverless] Update the Security Timeline Documentation in accordance with new Unified Timeline changes #5505 done by Mergify.

[mergify]

Cherry-pick of 1fe3f9e has failed:

On branch mergify/bp/8.15/pr-5505
Your branch is up to date with 'origin/8.15'.

You are currently cherry-picking commit 1fe3f9e0.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   docs/detections/images/ig-timeline.png
	new file:   docs/events/images/add-field-button.png
	modified:   docs/events/images/correlation-tab-eql-query.png
	deleted:    docs/events/images/create-a-timeline-filter.png
	new file:   docs/events/images/create-a-timeline-template-field.png
	new file:   docs/events/images/customize-event-renderers.png
	new file:   docs/events/images/remove-field-button.png
	new file:   docs/events/images/timeline-sidebar.png
	modified:   docs/events/images/timeline-ui-filter-options.png
	modified:   docs/events/images/timeline-ui-renderer.png
	modified:   docs/events/images/timeline-ui-updated.png
	modified:   docs/events/timeline-templates.asciidoc
	modified:   docs/events/timeline-ui-overview.asciidoc
	new file:   docs/reference/images/create-runtime-fields-timeline.png
	modified:   docs/reference/images/timeline-object-ui.png
	modified:   docs/reference/runtime-fields.asciidoc
	new file:   docs/serverless/images/runtime-fields/-reference-create-runtime-fields-timeline.png
	new file:   docs/serverless/images/timeline-templates-ui/-events-create-a-timeline-template-field.png
	new file:   docs/serverless/images/timelines-ui/-events-timeline-sidebar.png

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/explore/runtime-fields.mdx
	deleted by us:   docs/serverless/images/interactive-investigation-guides/-detections-ig-timeline.png
	deleted by us:   docs/serverless/images/timeline-object-schema/-reference-timeline-object-ui.png
	deleted by us:   docs/serverless/images/timelines-ui/-events-correlation-tab-eql-query.png
	deleted by us:   docs/serverless/images/timelines-ui/-events-timeline-ui-filter-options.png
	deleted by us:   docs/serverless/images/timelines-ui/-events-timeline-ui-renderer.png
	deleted by us:   docs/serverless/images/timelines-ui/-events-timeline-ui-updated.png
	deleted by us:   docs/serverless/investigate/timeline-templates-ui.mdx
	deleted by us:   docs/serverless/investigate/timelines-ui.mdx

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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