Allow for different styles of fretboard diagram

[Sintrastes]

Looking at some fretboard diagrams online, there are a lot of different styles.

We should have the option for things like background colors, fretboard inlays, or even horizontal orientation to allow users to customize these diagrams to their needs.

[Sintrastes]

Note: This could probably be stored as an aggregated group of preferences (a "style") that could be swapped in and out at will.

This would allow for things like allowing for different instruments to have different fretboard styles associated with them.