integration with OpenEmbedded and Yocto Project

[koehlma]

While it is possible to import a root filesystem built with a third-party tool into Rugpi Bakery, this requires a two-step build process for building the image. Instead, it would be great if there was a more direct integration into OpenEmbedded and Yocto. As we do not want to replicate the image building logic, it would be great if this integration could reuse Rugpi Bakery to build the image based on the filesystem built with OpenEmbedded.

Blockers:

• #27