add initial NTN support for NR UE
For the initial NTN support for NR UE, this is modified:
- add NTN specific parameter cellSpecificKoffset_r17 and use it for UL scheduling
- increase DURATION_RX_TO_TX by cellSpecificKoffset_r17
- set initial timing advance to NTN parameter ta-Common
- if no sr_ProhibitTimer is set, it should never expire
This is part of the work developed by Fraunhofer IIS within the ESA-funded project 5G-GOA (https://connectivity.esa.int/projects/5ggoa).