Add Raspberry Pi 4b support for Oniro

• Verify OpenHarmony-4.1-Release on rpi4b
• verify wifi support
• Fork rpi Board support packages (BSP) repositories in oniro4openharmony space
• Add manifest in https://github.com/eclipse-oniro4openharmony/manifest for rpi build
• Write documentation to reproduce build and flash
• Update CI to build rpi4b target and deploy artifacts