Support multiple JVM dependency code hosts on the same Sourcegraph instance

Created by: olafurpg

Currently, it's not possible to register multiple JVM dependency code hosts on the same Sourcegraph instance. This is not possible at the moment because there is no way for src lsif upload to target a specific JVM code host. It's typically possible to work around this issue by adding multiple Maven Repositories to the same JVM code host. Please comment on this issue or contact Support if the workaround is not sufficient for your use case.