OMG it works!!! This took me a week of off-and-on tinkering, learning,
procrastinating, and struggling. So awesome that it's finally working!

The `liftMaybe` was key, learned that from:
https://stackoverflow.com/questions/8684252/how-to-inject-a-maybe-value-into-maybet

This article on monad transformers by 'kqr' also helped quite a bit:
https://github.com/kqr/gists/blob/master/articles/gentle-introduction-monad-transformers.md

A Wikibooks article on the same was somewhat useful:
https://en.wikibooks.org/wiki/Haskell/Monad_transformers

And this was an interesting look at Alternatives, which I didn't end up
using but was interesting nonetheless:
http://www.parsonsmatt.org/2016/11/18/clean_alternatives_with_maybet.html

When I learned about monad transformers I thought: "Yes! This is what I
need to clean up the `privmsgFromPlugin` function.". I wasn't liking the
nested `case` statements there, and since everything was a `Maybe`, I
thought, why can't we chain the `Maybe`s like we're supposed to be able
to with monads? Well, turns out we can. It just involved a lot of tricky
`lift`ing. This gets rid of the nesting, resulting in a much cleaner-
looking function. So cool!

Going for readability in explicitness.

We're not using this any more so it can be removed. I had added when I
was originally experimenting with getting values from the database and
had been selecting the `id` field.

Move the CLI option extracting to a new function that moves the option
parsing logic outside the plugin.

Get the language from the command line options and use it to determine
which localised string to return on error. Wooo!! it works! So cool.

Add French translations for our existing strings.

The code to get the language option is pretty messy for the moment. I
want to factor it out into its own separate function. But at least it's
working now.

Instead of parsing `--language` as a string, parse it as a real `Locale`
type. This means the parsing is taken care of for us at the CLI option
handling stage instead of later on.

We can thus use the language value more quickly and easily, passing it
to the `translate` function, which takes a `Locale`.

Make the parsed options accessible to the rest of the program.

Provide a way to switch languages when starting the bot.

When talking with the bot in a private one-to-one query, there's no
reason to use the "sorbot: " prefix because you're not talking to anyone
else. In that case, just behave like we did before and allow users to
send commands with no prefix.