add deterministic chunk ids and make it default
StatsTestCases no longer need to explicitly use natural ids as the defaults are deterministic now too
add concept of id name hints for chunks
add `idHint` option to splitChunks to provide a hint
deduplicated code from different id plugins to IdHelpers
improve behavior of named ids in case of conflicts
remove `name: true` and `automaticNamePrefix` from splitChunks it's not as good as expected
improve named chunk ids to show root modules