Integrate meta-guf-machine/move_README_to_manifest

Commit: https://git.seco.com/seco-ne/yocto/layers/meta-guf-machine/-/commit/4ea51b32ed87547175953dd920436b5a19b28b18

README: Move README.md description to manifest

We described most of the project specific build instructions in the mat-guf-machine layer. This is not too convenient as the main entry point is the manifest repository.

Address that by moving the instructions to this manifest repository and later removing the description from the meta-guf-machine layer. Adapt the SECO name change here as well.

BCS 746-000659