[MANIFEST] Add meta-seco-bsp and meta-seco-distro layers
These layers have been added as a base for other internal layers: All layers are placed on the same level (layers folder), but the logical point of view places these newer layers as follows:
├── meta-seco-bsp
│ ├── meta-seco-imx
│ ├── meta-seco-rk
│ └── meta-seco-intel
└── meta-seco-distro
├── meta-seco-edgehog-embedded
└── meta-seco-edgehog-things
Edited by Davide Cardillo