Specifically,
- directly export `modules/lib/dag.nix` instead of renaming
attributes,
- run through utilities to reuse code where possible,
- expose `lib.hm.dag.isEntry` and reuse it in
`modules/lib/types-dag.nix`,
- reuse utilities through `lib` set instead of passing imports to
functions, and
- eta reduction of `map`, `entryAnywhere`, `entryAfter` and
`entryBefore`.