[DOCS] Adds runtime fields

[KOTungseth]

Summary

• Adds Explore your data with runtime fields to Stack Management.
• Adds Add fields to Lens.
• Moves runtime fields, scripted fields, and field formatter content to new Manage index pattern data fields section under Stack Management.

[elasticmachine]

Pinging @elastic/kibana-docs (Team:Docs)

[elastic-jb]

We might want to add something to the bullet about selecting type that clarifies that your scripts output MUST match the output type or the script will not work. They should get an error, but it's probably worth making it clear that it will not convert any types.

[flash1293]

Left some comments. Can be done later, but it would be cool to extend the tutorial to contain a real-world example of how runtime field can be used.

[elastic-jb]

I'm not sure I would use the language "we add fields to documents." I get the intent of what it's trying to say, but runtime fields are added to index patterns and that could be misleading in how it's worded. The first two bullets in the value list might make more sense reversed also, the schema-less concept being first.

In the list of product tools that work, we should be re-enforcing that they work anywhere an index pattern is used. Instead of an app to app concept to think about, the model is they work everywhere except.... and list anything that doesn't support index patterns.

For the create runtime fields section, we should use Discover or Lens as an example. Not everyone has access to index pattern management. That will be less limiting for someone wanting to try them.

The Lens page looks ok to me.

[KOTungseth]

I'm not sure I would use the language "we add fields to documents." I get the intent of what it's trying to say, but runtime fields are added to index patterns and that could be misleading in how it's worded. The first two bullets in the value list might make more sense reversed also, the schema-less concept being first.

I don't see "we add fields to documents" in this PR, but I reversed the bulleted list of benefits.

In the list of product tools that work, we should be re-enforcing that they work anywhere an index pattern is used. Instead of an app to app concept to think about, the model is they work everywhere except.... and list anything that doesn't support index patterns.

I've removed the list, but I'd still like to call out Discover and Lens in the bulleted list of benefits.

For the create runtime fields section, we should use Discover or Lens as an example. Not everyone has access to index pattern management. That will be less limiting for someone wanting to try them.

This section is geared towards admins, who should have access to index pattern management. For analysts that want to create runtime fields, they can refer to the Discover and Lens Add fields sections.

[KOTungseth]

@elasticmachine run elasticsearch-ci/docs

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