Update docs for new Gradle plugin

[3flex]

Expected Behavior

Current functionality is documented for users.

Current Behavior

Several updates have been made but not documented.

Context

Updating docs as we go will require too many changes, but they need to be updated before 2.0.0 release.

[cortinico]

@3flex do you need any help here?

[3flex]

I'll update once I'm finished with the planned changes, still a few things to take care of.