Break out analytics module documentation into various pages

[patmmccann]

Would be nice to mirror the formatting of https://docs.prebid.org/dev-docs/bidders.html instead of having one very run on page.

[muuki88]

You mean https://docs.prebid.org/overview/analytics.html should have the same layout like bidders.html and all the params should be on separate pages?

The pages are already there, but not properly linked:
https://docs.prebid.org/dev-docs/analytics/adagio.html

[bretg]

The existing analytics pages aren't quite ready for prime time -- they don't mention that this is an analytics adapter page. So I think the point of this issue is still valid - make updates to have analytics adapter pages be standalone and linked into an index page.