Remove/rename wrapper around setComponentTemplate

[pzuraq]

Currently, we wrap the VM's version of setComponentTemplate with a function that calls templateFactory on the serialized template block. This means the transform can be simpler overall, and we import one fewer function in each module, saving bytes, but it does not match the implementation in Ember, which requires us to pass in the template factory. We should either remove this wrapping layer and do it in the Babel transform, or we should rename it and export it as a separate utility function that the Babel transform can target.