implement options:
- options.overrides
- options.groups.<name>.overrides
Having this, it should not be necessary anymore to override members of a group directly. Instead the logic can be bound to package names, either globally for all groups, or locally for a single group.
We should probably also rename :
- `options.commonModule` -> `options.overrideAll`
- `options.groups.<name>.commonModules` -> `options.groups.<name>.overrideAll`