Claim file ownership for IMCE

Issue Summary

Hi.
Would it be possible and feasible to add a "Claim ownership of file to IMCE" option?

Currently if you upload a file through the Remote URL option in one node,
and afterwards try to select the same file using IMCE File Browser, on saving it says
"Referencing to the file used in the x field is not allowed."
It does that because the filefield_sources module has a reference to it, and there is none in imce_files.