Discuss replacement for jetty-runner

**jetty-12**

As `jetty-runner` is `@deprecated` in jetty-12 for several reasons - the new environment structure for one - we should discuss what, if anything, we can do to replace it.

One suggestion: create a maven archetype to make it easier to create an embedded jetty that runs a war.

Other suggestions welcome.

Start by reviewing the jetty-12 jetty-runner deprecation and the new environment structure mentioned in the issue. Evaluate the proposed Maven archetype alongside other replacement options, and define a decided replacement approach and its scope as the completion criteria.

Written by the indexing model from the issue text.