Sadly, Gradle handle's exclusions differently to Maven even when it's
processing a Maven pom.

In this case groovy-all is pulled in via org.crashub:crash.shell where
we've excluded it. This is enough to prevent Maven from pulling in
groovy-all when you depend on the remote shell starter.
org.crashub:crash.shell is also pulled in as a transitive dependency
of a number of other dependencies and Gradle requires each of these
to also exclude groovy-all for it to actually be excluded.

This commit adds the additional exclusions that are required to make
Gradle's behaviour sane.

Fixes gh-2257