[Feature] Add left-handed view switch

[terrestrian]

Currently, the way chord diagrams are shown appeals to right handed players. As a left-handed player, this is confusing and it would be really nice to be able look at the chords as reversed.

[bragefuglseth]

Thanks for your suggestion! I'd like Fretboard to be accessible to as many people as possible, so this is a great idea.

Seems like it's possible to set the text direction of the chord diagram to RTL to achieve this, so it shouldn't bee too hard to implement. Two radio buttons in the app menu seems like the most sensible way to expose this as a preference.

[bragefuglseth]

It was… not that easy. I had to modify the drawing logic and make some architectural changes. But now it's here! This will arrive in Fretboard 4.0.

[terrestrian]

That looks amazing! Thank you so much for your hard work.