Provide a means to migrate legacy BI data to Cycles/Eevee when opening older .blend files

There are a lot of .blend files out there which contain BI materials/textures/etc, and with the removal of BI many users will open these files and wonder why their materials/textures/etc don’t look right. To avoid confusion, there should be a dialog box warning users opening a file with BI data that it is incompatible, similar to how there is a warning when opening files saved by newer versions of blender. If possible, this would also present the user with the option to automatically migrate this data to work with the newer engines.

I believe the add-on “Materials Utils Specials” provides functions to convert BI to Cycles, which may be a good starting point for automatic conversion.