Replaces the old Gradle plugin with plain Gradle buildscripts. Also cleans-up
the current Gradle extensions and re-adds detekt, along with JUnit 5 support to
all modules.
Allows parameterized tests to use Item, Npc, and Object definitions
as @ArgumentSources.
This commit also adds support for using @ItemDefinitions etc on
properties as well as functions.
Updates the testing infrastructure to use the latest relesae of junit and
leverages the new extension mechanism to create an easy to use testing
framework. Also adds additional test coverage for several plugins.
Gary Tierney