Split hildon-meta package into a minimal meta package and a full meta package

[MerlijnWajer]

It could be useful to provide a more "minimal" image for certain use cases. One example is for flashing Maemo to the mz617, then it would be useful if it could fit in some smaller partitions.

We probably also don't want to generate all the locales for the more minimal images.

We will also need to make a slimmer hildon-meta package.