Work on BeagleBoard.org platform support and templates:

1. BeagleBone Black was used in headless mode due to SGX issues since Kirkstone (Octopus, Pike, etc) - it got fixed recently in meta-ti and may need updates in AGL

2. As meta-ti recently changed the way K3 multiconfig TMPDIRs are handled for different cores (baremetal vs. Linux) and introduced shared DEPLOY_DIR - this may affect existing j721e-evm

3. Add support for the new BeagleBone-AI64 platform based on j721e-evm - higher-end platform with lots of different cores and accelerators

4. Add support for the new BeaglePlay platform based on am62xx-evm - lower-end low-cost platform meant to eventually replace aging BeagleBone Black