Data lifecycle docs: Recommended rollover settings

[kilfoyle]

Note: I'm opening this as a separate issue from the other Rollover docs updates, because recommended settings can take a lot of effort to gather and explain.

Feedback on Rollover (16:28):

• When I enable rollover, why would I change the settings there:

  • Maximum primary shard size
  • Maximum docs in the primary shard
  • Maximum age
  • Maximum documents
  • Maximum index size

• What are typical, recommended settings?