Use kordamp Gradle plugins

[robertpanzer]

Let's consider using the kordamp Gradle plugins: https://aalmiray.github.io/kordamp-gradle-plugins They should reduce the complexity of the build. This requires a migration to Gradle 5 as reported in #747 first (or in parallel if this really makes things sooo much easier).

[mojavelinux]

cc: @aalmiray

[mojavelinux]

cc: @ancho

[aalmiray]

I can have a look at this in the coming days. Will push a branch to my fork and let you know.