Prettier 2: Electric Boogaloo (#6113)

# Description of Changes
When I added Prettier formatting in #6052, my aim was to use just the
default settings in Prettier. Turns out, Prettier looks _really hard_
for any config files if it's not explicitly given one, which means that
if a developer has some sort of Prettier config file lying around on
their system, Prettier might find it and use it. Also, Prettier changes
its defaults based on stuff in `.editorconfig` without any good way of
disabling that behaviour explicitly in its config file.

To solve both of these issues, I've introduced a `.prettierrc` file
which sets Prettier's defaults explicitly, and then reformatted all our
code _again_ in Prettier's actual default settings. This should achieve
the aim of #6052 and remove the possibility for it breaking on different
dev computers.

frontend/src/core/components/onboarding/tourGlow.ts

@@ -12,6 +12,10 @@ export const addGlowToElements = (selectors: string[]) => {
 };
 
 export const removeAllGlows = () => {
-  document.querySelectorAll(".tour-content-glow").forEach((el) => el.classList.remove("tour-content-glow"));
-  document.querySelectorAll(".tour-nav-glow").forEach((el) => el.classList.remove("tour-nav-glow"));
+  document
+    .querySelectorAll(".tour-content-glow")
+    .forEach((el) => el.classList.remove("tour-content-glow"));
+  document
+    .querySelectorAll(".tour-nav-glow")
+    .forEach((el) => el.classList.remove("tour-nav-glow"));
 };