'Getting Started' is dated

[f4lco]

In response to #233: we should updated the 'getting started' page with recent build instructions,

• no jcenter
• no legacy plugin syntax
• no plugin scripts
• maybe even add Kotlin DSL

This site should hold up to https://plugins.gradle.org/plugin/org.gretty, maybe we can also just link that page instead of replicating its contents.

[kuzmeo]

Hello!

Seems like gretty documentation is outdated at https://gretty-gradle-plugin.github.io/gretty-doc/Gretty-configuration.html
I'm trying to upgrade to gretty 4.0.0 from gretty 3.0.5. and, for example, found correct value for servletContainer property not in the documentation, but at Gitter https://gitter.im/gretty-gradle-plugin/gretty?at=6042603b95e23446e414b3ea
It would be nice to have gretty-doc updated for gretty 4.0.0. version :)

[boris-petrov]

@kuzmeo - thanks for the heads-up! PRs are always welcome in the documentation repo. :)