Bluetooth: Tester: Add Blob, DFU and DFD tests support

Adding support for automatic testing BLOB, DFU and DFD models.

Co-authored-by: Agata Ponitka <agata.ponitka@codecoup.pl>
Co-authored-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>
Signed-off-by: Krzysztof Kopyściński <krzysztof.kopyscinski@codecoup.pl>
Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>