Support custom fonts

[i-am-the-slime]

It's possible to specify fonts as input to D2 via the CLI arguments:

• --font-regular
• --font-italic
• --font-bold

It would be very nice, if I could use the same from within Obsidian, since the default font d2 uses is very ugly.

[i-am-the-slime]

I was just about to file an issue for this again, it seems.