Provide documentation for Analyst Experience components

[dej611]

Problem: We need a way to showcase all of our components in one place for all of Analyst Experience. Solving this problem is important for the scaleability and adoption. The following is just a proposal and the actual implementation needs to be discussed.

Describe the feature:

Leverage the current storybook system in kibana to provide better LensEmbeddable documentation to consumers.

I've put together a quick example of the doc shape using the unified search stories:

So the idea is to put the LensEmbeddable within free text as in the EUI documentation with available source code to copy and paste directly.

Ideally some mocks will be required to work, and the unified_search ones I think are a good starting point (others can be inferred from Lens testing, and probably will need to more some expressions - i.e. data fetching).

There's already another example which can work as inspiration from the infra team:

[elasticmachine]

Pinging @elastic/kibana-visualizations @elastic/kibana-visualizations-external (Team:Visualizations)

[clintandrewhall]

This PoC may be of interest.

#150480

cc: @rshen91 @daveyholler

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[kertal]

cleaning up a bit, it's been a while, should we keep this open?