[Docs] Document the Add Data UI Feature

[Bargs]

@palecur This will be my first major contribution to the Kibana docs, so I may need some help.

Any rule of thumb for how detailed the docs should be? Once the user gets into each wizard, it should hopefully be somewhat self explanatory with the addition of inline help. For the pipeline creation step in particular, how much should we explain vs linking off to the Elasticsearch docs since most of the UI is a CRUD interface for the ingest node processors?

Here's my rough idea of what needs to be updated.

Todo:

• Put extensive documentation on the wizard pages themselves. The user shouldn't have to context switch to the docs for almost anything.
• Update "Getting Started With Kibana" section to instruct the user to navigate to the "Existing Indices" section to create their first index pattern (since it's no longer the first page they'll see).
• Mention that the Add Data wizards exist

[Bargs]

We talked about the actual design of the in page docs some today and decided to pursue a solution with a few different pieces:

• We'll add lots of help text to Wizard form inputs to guide the user. All of the help text should live in a file separate from the Angular templates, similar to what I'm doing with the dynamic doc links [Docs] Create dynamic links to docs in the Add Data wizards #6813. This work is tracked in Add help text to form fields throughout the Wizard #7062.
• We'll add short descriptions for the ingest processors on the pipeline page. This will probably take the form of a rich select box. [Pipeline] Give users info about each processor before they select them #7061
• After completing the above steps, if we still feel like we need additional long form in app documentation we'll begin work on a reusable documentation viewer based on Jurgen's prototypes.

@BigFunger @alt74 @rashidkpc @debadair Let me know if I've missed any takeaways from our convo.

[palecur]

Doc added for Alpha 4 as part of the Getting Started tutorial.

[Bargs]

[epixa]

I'm going to close this since the add data ui was pulled. We can always refer back to this issue if/when we revisit the feature.