A first step towards refactoring the module.
Unfortunately the config is not consistent in using comma-separated
values or repeated keys for lists, since the user can always add commas
by themselves, we should default to repeated keys in the generator.
This switches the type of `matchBlocks` from `loaOf` to `listOrDagOf`.
The former has been deprecated in Nixpkgs. The latter allows
dependencies between entries to be expressed using the DAG functions.