Document ghidra usage

Document the flow for obtaining traces of one or more files and visualizing them in Ghidra:
- install ghidra and add ghidra_cov_analysis.py to scripts dir
- kafl_fuzz.py to create a corpus
- kafl_cov.py to create trace files
- ghidra_cov_analysis.sh to sort out unique found edges and return coverage report

Start by following the listed flow with Ghidra: install it, place ghidra_cov_analysis.py in the scripts directory, use kafl_fuzz.py to create a corpus, and kafl_cov.py to create trace files. Check ghidra_cov_analysis.sh for the unique-edge and coverage-report steps. Done means the repository documents this complete flow for one or more files.

Written by the indexing model from the issue text.