Fix the whole italian Translation file

[Soumyaditya25]

Checklist

I have followed the Contributor Guidelines.
The code has been thoroughly tested in my local development environment with flake8 and pylint.
The code is Python 3 compatible.
The code follows the PEP8 styling guidelines with 4 spaces indentation.
This Pull Request relates to only one issue or only one feature
I have referenced the corresponding issue number in my commit message
I have added the relevant documentation.
My branch is up-to-date with the Upstream master branch.
Added Italian translations for scan comparison (issue: #905 )

Changes proposed in this pull request:

Fix the whole Italian translations for the it.yaml localization file.
Resolves issue #905.

[x ] Localization improvement

[x ] I've followed the contributing guidelines.

[x ] I've run make pre-commit, it didn't generate any changes

[x ] I've run make test, all tests passed locally

[securestep9]

Please test using command:

python nettacker.py -L it -h

I see some gaps

[Soumyaditya25]

@securestep9 I have tested several times and have not found any gaps.Please let me know if you need further test .