Allow customization of resource dialog source selector label

[garuma]

The current labels are "Local" and "Shared" which mean nothing in an Android context (rather they should be "Project" and "Framework").

When the ResourceSource is created on our side we do pass in those names but they don't seem to be bound in the UI.

[ermau]

The ResourceSource names are not for this, they are for placement locations / identification. They should be things like dimen, string, drawable, etc. "Local" and "Shared" are analogous to "Project" and "Framework" respectively.

We'll need some localization options for a few things, so we can look at adding this as part of that.