Improved multi language support

[4B3l0]

We wanted something a bit more advanced for our language management, so we decided to improve Serpico multi language support.

A finding can now have multiple language
We added a new class in the model : TemplateFindingsTranslation
Thanks to this class, a vulnerability can now have multiple language, wich is more practicale than having the same vulnerability multiple time in different language.
It's easier if you want to modify a field (like finding type or the CVSS parameters), you only have to modify it in one findings instead of in every language version of this findings you made.

When edditing the template database, for each finding you can acces a language panel which allow you to do three things :
Define the language of a finding

If no language was defined for this findings, you can do it from this menu

Add new language to a finding

If the finding doesn't have a translation for one of the language defined in the config file, you can add it from this menu

Select wich language to show

If there is multiple translation for the template, you can show wich one you want to show

Compatible with current multi-language support
Findings translated with the curent version of Serpico will be updated to match the model of the pull request at the first Serpico launch