Explore possibility of markdown for record descriptions

[allysonlister]

A user has requested that our descriptions be written in a simple (perhaps cut-down if it helps!) markdown format. @knirirr has mentioned that "we could store markdown data in Postgres but it would be necessary to have the record pages interpret the markdown. There's probably a Vue package to do that, but I would have to investigate. It might also need a markdown editor on the editing page."