A Minimal Chisel Development Environment with Mill

The project is here, with instructions of setting everything up in the README file.

So here, instead of reiterrating the set up flow, we will document some design choices of doing things.

Scala build file

Mill will look for build files named as `build.sc`, `build.mill`, or `build.mill.scala`. We decided to use build.mill.scalaas it makes it cleaner that a) this is a build file for mill, and b) this is a file with scala syntax. build.millis another decent option, but unfortunately Github does not recognize this file extension name, and cannot properly do code highlighting.

Source directory organization

For some reason, the build system cannot find the Elaborate.scala file if it is placed under /src/main/scala/. Instead, the current build system searches for source files under <TopLevelObjectName>/src/main and <TopLevelObjectName>/src/main/scala.

Therefore, we now have this a bit awkward YourChiselProject folder.