Sufia 7.2 migration Reads GenericFile content into memory

[carolyncole]

Descriptive summary

In Sufia 7.2 Migration the version importer reads the entire content into memory. https://github.com/samvera/sufia/blob/7.2-migration/lib/sufia/import/version_builder.rb#L38

This works fine for small files, but when you start migrating larger files you can run out of memory.

Expected behavior

Stream the file from Fedora instead of doing a single read

Actual behavior

Reads the entire content into memory

Related work

We fixed this in ScholarSphere here: psu-libraries/scholarsphere@8f3f0d1#diff-2897df61a9e8723e3a0f8b8ee15638fcR51