Added NTN FDD FR1 bands defined in 3GPP TS 38.101-5
Added support for NTN FDD FR1 bands 254, 255, 256 as specified in 3GPP TS 38.101-5. Example Conf files added for band254 for 15Khz, 5Mhz and 30Khz, 10Mhz configurations. Tested NTN GEO configuration on band 254 using these conf files.