[Feature]: Change border color of common items

[kalbert312]

Describe the feature

The ability to change the border color of common items, or classes of items in general. Similar to #326.

Describe the implementation

Get configurable support for changing the common item border color, or classes of items in general. It is currently white and on my favorite Masque skin "Caith", it's jarring to see a backpack full of white borders. I would prefer in this case that common items have a black or very dim border. See screenshots below.

I'm also willing to create a PR for this, but I see themes are planned so I figure it would be obsoleted quickly.

Another recolor I want to try is setting "Junk" to red.

Current:

Desired: