Common container should apply plugins before invoking source sets

[05nelsonm]

All other target containers invoke applyPlugins before configuring source sets. This too should be the case for the common container such that plugins are in fact applied (and their dependencies added) before sourceSetMain or sourceSetTest are invoked such that extension configuration can be had there if need be. The way things are now, any extensions applied in common.pluginIds must be configured in the kotlin lambda.