Develop nbiotconf shlibloader

1. shared library loader, with integration for oai devices, encoder and telnet server
2. telnet server (use build-oai --build-telnetsrv option and --telnetsrv softmodem option)
3. UE/eNB in different executables (lte-uesoftmodem and lte-softmodem + noS1 variants)
4. config module fixes and extensions
5. very preliminary NB-IoT integration preparation, using shared lib loader ( use make NB-IoT to build, after building the eNB softmodem)
6. Rename NB-IoT configuration sources from nbiot_ to NB-IoT_ to be consistent with other NB-IoT developments.