Add a new column Issue states that can be sorted on

[Enselic]

That way it is much easier to find FIXMEs for issues that are fixed, because one can sort on issues that are "Closed".

I'm sure there is a way to present this in a better way, but this is already a significant improvement, so is a reasonable starting point for further tweaks.

For rust-lang/rust#44366

Edit: Looking at the CI logs, it amazingly looks like getting issue states works. When it does not work, it should look like this:

HTTP GET issue state for 41620
error: GitHub: Bad credentials
Documentation URL: https://docs.github.com/rest

[oli-obk]

Very neat!