Improve index documentation

[malarzm]

While answering http://stackoverflow.com/questions/41172585/index-not-created/41173619 I found that it's actually hard to find anything about creating indexes in the docs (there's small paragraph by the end of Embedded Indexes). Also Console Commands chapter seems to be reachable only from that very sentence in indexes, might be good to expose them on the front page as well.

[olivmaurel]

Hi, I can update the documentation if it's still needed

[malarzm]

@olivmaurel that'd be awesome!

[stale]

This issue has been automatically marked as stale because it has not had any recent activity. It will be closed in a week if no further activity occurs. Thank you for your contributions.

[alcaeus]

Bad bot...