Add `laikaServe` target to the Mill buld.sc script

[hmf]

The URLs generated by Laika have the index.html files stripped from the SpanLinkelements. This does no allow simple local browsing via the files system. To solve this we need to use customize the renderer. It may be easier and better for development and testing purposes to simply create a server for this.

References:

• https://github.com/com-lihaoyi/requests-scala
  • https://www.lihaoyi.com/post/HowtoworkwithHTTPJSONAPIsinScala.html
• https://github.com/com-lihaoyi/cask
  • https://com-lihaoyi.github.io/cask/
  • https://www.lihaoyi.com/post/SimpleWebandApiServerswithScala.html

Notes:

• http://www.lihaoyi.com/post/comlihaoyiScalaExecutablePseudocodethatsEasyBoringandFast.html