Backup.sh: Add options for Licenses to be stored

[OWarneke]

It should be possible to select between SD Card License and PLCnext Store Licenses.
Also include an option to support and auto detect the Source and Target SD Card.
Differentiation must be made between:

SD FLASH 8GB PLCNEXT MEMORY LIC (item no. 1151112)
SD FLASH 32GB PLCNEXT MEMORY LIC (item no. 1151111)
SD FLASH 8GB PLCNEXT MEMORY (item no. 1061701)
SD FLASH 2GB PLCNEXT MEMORY (item no. 1043501)

"PLCNEXT MEMORY LIC" SDs consist of multiple partitions , "PLCNEXT MEMORY" SDs however hold only one partition.