files.elf settings should be migrated to load settings

[psifertex]

See: https://github.com/Vector35/binaryninja-api/blob/dev/view/elf/elfview.cpp#L25-L52

Not sure about a migration plan, might just have to make a hard-cutover and document? I don't know that a settings alias will work migrating to a load setting (I suspect it won't)