Update backlinker.py

[simeononsecurity]

Change Description: The updated code allows the script to accept a website as a command-line input parameter and provides more verbose output. Instead of exiting the script immediately when encountering an error, it prints an error message and continues with the next backlink. Additionally, it handles the case when the "urlbacklinks.json" file is not found and provides an appropriate error message

python3 backlinker.py example.com