Enable us to use tailwind's
[`font-family`](https://tailwindcss.com/docs/font-family) classes as
well as remove `gt-mono` in favor of `tw-font-mono`. I also merged the
"compensation" to one selector, previously this was two different values
0.9em and 0.95em. I did not declare a `serif` font because I don't think
there will ever be a use case for those. Command ran:
```sh
perl -p -i -e 's#gt-mono#tw-font-mono#g' web_src/js/**/* templates/**/*
(cherry picked from commit 226a82a9396dc94f362ba27bd1c9318630df74b4)
bcfb7e0356