* Update releases.mdx

* use latest versions

* add changelog

* update title

* add a reference page on resource limits and fees

* remove resource fee/limit tables from "explainer" page

* removing some unnecessary comments and entries

Some of the comments are more applicable in the discussion doc,
than they are for developer documentation. So, let's get rid of
those.

* remove unnecessary "current is..." language from resource fees

Refs: #728