[Maps] Add documentation for the Maps application

[alexfrancoeur]

Placeholder for beta docs for the Maps application

[elasticmachine]

Pinging @elastic/kibana-gis

[alexfrancoeur]

After the PMM discussion today, it would be nice if we had docs explaining specific features but also a "getting started" flow, similar to getting started with Kibana. We could easily leverage a sample data set here.

[alexfrancoeur]

@elastic/kibana-gis any chance we can incorporate in context documentation (#29664) for Maps in 7.0?

[thomasneirynck]

@alexfrancoeur do you have examples of plugins that are currently using it?

[alexfrancoeur]

@thomasneirynck the APM team are the first trailblazers I believe #30918

[thomasneirynck]

I'll label it with v6.7/v7.0 for now. See if we can find time to add this when we're writing docs.

[gchaps]

Maps documentation is here, including a Getting Started. The GS leverages the web logs sample data set.