Autofill: add support for current/any source entity

@wombatbuddy, created a patch for it please verify.

I found that this solution does not work for drafts. But I'm not sure if this is a bug or a feature.

The last submitted patch, 2: 3402006-1.patch, failed testing. View results →
- codesniffer_fixes.patch Interdiff of automated coding standards fixes only.

The patch needs to be fixed. Drafts should probably not be used via autofill.

If there is no genuine interest in this feature. I might not commit it.