When debugging make variables output optional

[Mzack9999]

Nuclei version:

main and dev

Current Behavior:

The -debug flag prints out request/response + variables, making the output unreadable

Expected Behavior:

Variables should be printed in a more concise way (eg. batched inline) or only if requested

Steps To Reproduce:

$ go run . -t test.yaml -debug -u http://scanme.sh
...
[DBG] Protocol response variables:
        1. Scheme => https
        2. service => sts
        3. BaseURL => http://scanme.sh
....
        100. File => /
...

[ehsandeep]

@Mzack9999 this is already done in dev, as part of #2670

[Mzack9999]

Duplicate of #2670