Add more to Data Privacy chapter

[cansavvy]

#18 started the Data privacy chapter but needs more filling out:

• The how to protect this info needs more work. I'm finding it hard to write this section given the wide variety of situations and data types and institutional policies that might be going into play.
• Note I also wrote a brief What genomic data is protected? and I would like to add other sections that describe imaging or other types of data, but I don't know anything about these data types so I wasn't really able to figure out what to write for those.
• I don't have any comics or visuals here yet.