Device-specific Cellular API extensions

Topics
	HL7800
	Sierra Wireless HL7800 cellular modems.
	HL78xx
	Sierra Wireless HL78xx cellular modems.
	SIMCom SIM7080
	SIMCom SIM7080 cellular modems.
	ST87Mxx
	STMicroelectronics ST87Mxx cellular modems.

Detailed Description