Facades and NotSupported assemblies are bloated with resources they don't use

Often times we have builds that cross-compile and have very different implementations. Our resource conventions don't force folks to think about this, so the resources are often a superset of all configurations.

We should change the defaults so that this isn't the case.

I propose the following:

1. By default PartialFacades should not include any resources, unless a project opts-in. Folks should discover this relatively easily as SR.Foo will fail to work in the partial source. They can fix it by setting a flag and potentially providing specific resources for that build of the library.
2. By default NotSupported assemblies require a unique resx. We can change the path convention to something like Resources\NotSupported.resx instead of strings.resx

Across all our builds this will save over a MB of unused resources.