CB-8229 Gradle: Add CordovaLib as a dependency to all plugin sub-projects
CB-8228 Gradle: Allow plugins to use Maven dependencies
Merge branch 'master' into 4.0.x (gradle - maven and CordovaLib dep)
CB-6630 Delete bundled (and outdated) copy of OkHttp

Those that want to use OkHttp can use a plugin.