* Rename some base_url values in Paradox.scala
* Rename Akka to Pekko in documentation, also adapt/remove small blocks of text that were no longer consistent or adequate
* Rename Akka to Pekko in some related files outside the doc directory
* Rename akka-bom to pekko-bom
* Rename artifacts prefixes from akka to pekko
* Add links to Apache documents in licenses.md
* Add links to Akka migration guides for earlier versions
