Annotate Grails completion results with origin info

```
see OriginInfoAwareElement.getOriginInfo()
```
This info should describe how implicit method or property was created (Controller implicit method, delegated from some class, etc)

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*Imported from [IDEA-93358](https://youtrack.jetbrains.com/issue/IDEA-93358) · Type: Feature · Votes: 0*
*Comments, attachments, dates and reporter are not part of the export — follow the link above for the full history.*

Start by locating OriginInfoAwareElement.getOriginInfo() and the completion-result handling it relates to. Determine how implicit methods and properties are represented, including controller methods and delegated elements. Done means completion results are annotated with origin information describing how each implicit member was created.

Written by the indexing model from the issue text.