Remove deprecated Jetty plugin about gradle

[big-guy]

I think we have things that use jetty, but not the jetty plugin. Do you think we would need to update things that use jetty (e.g., all of our HTTP/repo mocking infrastructure)?

[bmuschko]

We can continue to use Jetty for testing infrastructure. That's totally fine. This work really is only about the fact that were are going to remove the Jetty plugin and therefore need to change everything that depends on it.

[bmuschko]

@eriwen Why did you remove the milestone for this issue? The deprecation message and our documentation says that the plugin will be removed with 4.0.

[eriwen]

@bmuschko Mistake on my part. We aren't doing any new deprecations in 4.0, but since this is already deprecated I'll put it back on the 4.0 milestone

[pioterj]

Remember to remove it from the user manual too.

• Obviously https://docs.gradle.org/current/userguide/jetty_plugin.html
• Also https://docs.gradle.org/current/userguide/web_project_tutorial.html

[pioterj]

And from https://docs.gradle.org/current/userguide/standard_plugins.html

[eriwen]

Closing as complete