Logic for getting and setting the context classloader we'll use for loading Metabase plugins. Use `the-classloader`
to get the Classloader you should use with calls to `Class/forName`; call it for side effects to ensure the current
thread context classloader will have access to JARs we add at runtime before calling `require`.

The classloader is guaranteed to be an instance of `DynamicClassLoader`, which means we can add URLs to it at
runtime with dynapath; use `add-url-to-classpath!` to add URLs to the classpath to make sure they are added to the
correct classloader.

If you are unfamiliar with ClassLoaders in general, I found this article pretty helpful:
https://www.javaworld.com/article/2077344/core-java/find-a-way-out-of-the-classloader-maze.html.

<3 Cam

Helpers to make it easier to nicely print our custom record types in the REPL or elsewhere.