[Task]: Develop instructions on how to change boot logo

[igorpecovnik]

File: https://github.com/armbian/documentation/blob/master/docs/Developer-Guide_Build-Options.md

Build time and run time.

When done, open a Pull Request and once merged its eligible for entering the pool to win one premium and one standard Khadas Mind portable workstation! 🥇

https://www.armbian.com/newsflash/armbian-khadas-are-rewarding-contributors/