add flash size to command "detect"

Expand the "detect" command to return the flash size or implement a new command line parameter.

Use the already implemented get_size function inside the flasher.

Return flash parameter to netXStudio to allow the netXStudio the parameter validation.

This is required for all external tools using the flasher to provide the connected flash size.

The flash size is used by external tools to validate, if the size of the selected file fits to the flash size.

This is used to calculate a start offset inside the flash for the SW or FDL, which has to be located at the end of the flash.