source module (for improve error reporting)

often when a module fails the first thing you want to know is which module is the dominator.

This PR needs to also follow up with error logging that understands sourceModule

cc @lukemelia

```
ENOENT, no such file or directory '/Users/stefan/src/ember-cli-addon-search/tmp/tree_merger-tmp_dest_dir-kqA7qMqs.tmp/ember-cli-addon-search/config/environments/test.js' imported by: ember-cli-addon-search/tests/helpers/start-app
```

Also we tag along all the important information, so improved future loggers can display more granular output
I am somewhat concerned that overriding `err.message` here may make tracking down non-import errors difficult.