Renamed layer to 3dp

the three letter acronym 3dp stands for 3D Printer

Signed-off-by: Christian Ege <k4230r6@gmail.com>
Added an append file for the core-image-base image

This is mainly for debugging purposes.

Signed-off-by: Christian Ege <k4230r6@gmail.com>
Fixed several issues within the octoprint bb file

Signed-off-by: Christian Ege <k4230r6@gmail.com>