Add config output jars to current_jars

[ramyanaga]

This change does the following:

• rename ConfigJavaInfo to ExtraDependencyProviders and rename the field config_java_info to extra_java_deps
• update the type of extra_java_deps from single struct to list of structs + update the code to handle the list
• add the class jars from extra_java_deps to current_jars

[johnynek]

Can we find a better name than ConfigJavaInfo.

Something like ExtraDependencies or something? I don't know.

[eed3si9n]

These are somewhat conflicting adds.

1. java_info_runtime_deps would bypass the jarjar (Jar Jar Abrams), and will NOT be shaded thus I've suggested the name ConfigJavaInfo indicating this should contain text files only.
2. current_jars would go through the jarjar, and the contents will be subject to jarjar rule. I guess we've confirmed that JSON would pass through, so should be ok.

I think having both are wrong here.