feature: add field to track patent protections

[tlambert03]

feature request from contact form:

Is it possible to add some kind of information about intellectual property protections of fluorescent proteins in the database?

Having recently switched from academia to biotech, I'm suddenly having to worry about whether a particular fluorescent protein is protected by patent, and whether it can be easily licensed. I would find it immensely helpful to be able to filter out fluorescent proteins that are patented.

I realize that a comprehensive answer might require input from patent lawyers, but I think it might be possible at a first pass to see whether the primary reference for a fluorescent protein is preceded by a patent from the same authors. After that, it would also be helpful to propagate these patent protections along lineages already in FPbase. For example, mCherry is patented, so I believe derivatives are also protected by the same patent, and may have additional patents. And as I understand things naturally occurring FPs are non-patentable, so adding a flag for that may also be helpful.