Fixing resume issue condition

[Mzack9999]

Description

This PR fixes the following issues:

• Index not zeroed per blackrock iteration (Fixes Resume doesn't reset the index at the end of iteration #326 )
• Adds maximum length check on Windows (Fixes Could not run nmap command: (The filename or extension is too long) #316 )

Example

Blackrock iteration:

echo 192.168.1.1 | go run .
# Hit CTRL+C to interrupt scanning
echo 192.168.1.1 | go run . -resume
# Observe that the resume point starts at the exact index if the retry iteration is > 1

Length Check on windows:

# On a windows system use a target with a lot of open ports (eg. 1000) and observe that if the total nmap command length exceeds 2048 characters the command is only suggested
$ echo 192.168.1.1 | go run . -tp 1000 -v -nmap-cli "nmap -o nmap.txt"
...
[INF] Running CONNECT scan with non root privileges
[INF] Found 1000 ports on host 192.168.1.1 (192.168.1.1)
192.168.1.1:443
...
[INF] Suggested nmap command: nmap -o nmap.txt -p 1,2,3,4,5,6,...,1000 192.168.1.1