Add support for Phosphor Icons

[Michoels]

Phosphor Icons is a fantastic free icon set with over 9,072 icons.
It's my go-to library due to its vast size, uniform quality, and regular updates.

The core library of all 9K icons (across all 5 weights) is here.

While there already is a 3rd party gem, it would be great if this project could add support.

I'd be happy to help out with this.

[eelcoj]

@Michoels Coincidence, started this PR yesterday #40 🙌

[Michoels]

Fantastic!
Looking forward.

[eelcoj]

If you have thoughts/ideas on the task for “filename normalization”, I'm all ears!

[Michoels]

Off the top of my head, there are probably two main approaches:

1. Rename the files at download time (requires customizing the download system)
2. Rewriting the user's requested icon name at runtime (requires customizing the runtime helper)

Which is better?
That depends on the internals of this gem, but my gut feeling is to go with (1) because I'd sooner have a custom downloader (runs once) then a custom helper (runs thousands of times per user on the render process). The risk is a failed download, and not failing a view render in real time.

[eelcoj]

For sure on download is the moment. Currently it simply moves the icons from the cloned repo to the library. That's likely where any file -transformation can be done.

[Michoels]

In the past, I've architected systems like this by mimicking the ActiveRecord hooks API: before_move, around_move, after_move.

The icon library adaptors can then hook in to whatever they need.