Do not use the default namespace for the `maven.install` tag

[shs96c]

Using the default maven namespace causes pollution for projects that depend on rules_closure. I'm attempting to use rules_closure with Selenium itself, and introducing the ruleset has lead to the unusual condition that we now depend on our own published jars.

In rules_jvm_external we advise against rulesets included via bazel_dep from using the default namespace (in this section) Perhaps closure_deps could be used instead?

[gkdn]

Would you like to send a patch?