[ACCTON][AS9947-72XKB] Add new platform

[WillyLiu-EC]

CPU : Ice Lake-D (D-1734NT 8C) MAC: Broadcom J2C+ (BCM88851), 2 pcs , 7.2 Tb/s integrated packet processor Ethernet Ports: 24 x QSFP-DD ports & 48 x QSFP28 ports shared with 4 x 10G SFP+ Power Supply: 12V/3200W PSU back to front airflow (DC to AC), 1+1 redundant load-sharing, hot-swappable Cooling: 4+1 FAN-tray modules with 5 pcs of 80mm x 80mm x 130mm 12V hot-swappable fans, 15400 RPM. 2+1 FAN-tray modules with 3 pcs of 40mm x 40mm x 93mm 12V hot-swappable fans, 31000 RPM. BMC Module: AST2600