fix(people): sort order by last name

[louh]

I don't know what the sort by score means since almost everyone has 1 (except for Mark and Annabel). It looks like this causes the published website to sort overlords by first name, then score, but if you're running a local version then all bets are off, it's sorted by random, then score. (With the exception of accomplices, which are sorted by last name.)

I'm proposing to make this consistently sort by first name only across all three categories and removing score from sort order which doesn't seem to serve a purpose (that I know of!)

I kind of like the option of sorting by random, to be honest, but that's not something I think gatsby/graphql can do. (We'd have to tell React to render items at random, which is also fine.)

[slifty]

I also really like the idea of random, but this is a great in-the-meantime improvement.

[louh]

Thanks -- merging now, but opening issue #139 for a follow up PR.