Update the log formatting and enhance the readme file content

[oliveiraleo]

Hello,

I tried to reproduce your work and found that some improvements could be made and contributed upstream.

I've updated the onscreen log pattern generated by the NWDAF implemented by you (so it could match the pattern used by free5GC on v3.3.0) and enhanced the readme to give much more detailed instructions for the community that may use your work as reference in the future.

Inspired by this PR #6 I've added the citation information to the end of the readme file.

I already prepared a PR with the suggested changes however feel free to change it or contact me if needed.

Thanks in advance, oliveiraleo.