Set DFU bootloader name

Set DFU bootloader name

Fixes #22

Each (dfu) interface may have more than one a ltsetting each with their own index and name. According to the DFU_1.1 pdf section 4.2.3, "* Alternate settings can be used by an application to access additional memory segments. In this case,
it is suggested that each alternate setting employ a string descriptor to indicate the target memory
segment; e.g., 'EEPROM'." Whether or not we end up using multiple memory segments it is still good to have a descriptive name incase there are other dfu devices connected.