Add customizable board colors and textures

[Naviary2]

The game is lacking a lot of color! White and grey may not appeal to everyone. This I believe is one of the most important next features, and one that would attract more people, including streamers, to try out the game! We need a good first impression on people. Suggestion:

Add a gear-icon in the top right-corner of the header, that one clicked on, will open a settings drop-down that will allow you to customize the color of the board squares, or choose a texture for them, like for example, wood, or marble.

Here are some screenshot examples from how lichess.org does it:

[xa31er]

on it!

[Naviary2]

on it!

🔥 I've made a list some time ago of colors I thought look good on the infinite board! https://discord.com/channels/1114425729569017918/1114492409598967819/1168330900732391445