[ENH][TRA] Admin Interface (UI): Fixing untranslatable texts in lib/prefs/feature.php and global.pref

As reported by hman, lib/prefs/feature.php and global.pref contained untranslatable texts that means texts not processed with the tra() function and this result to that when we change the language those texts change the language those texts can't be translated even if they are translated in the language.php file corresponding to the the target language. To fix that I started by processed the reported texts by hman by the tra() function and change the tiki language in french and look at theadmin interface to see that the problem is resolved and I founded that the problem was resolved for some texts and not for others. For those texts for what the problem was fixed I found that it's due to no translation of the texts in the language.php file for the french(the texts was comment and not translated) and for others, the texts didn't exist in the language.php file. To solve that I uncommented and translated the texts that was not translated and for those that didn't exits I added them in the language.php file for the french language and translated them in french. The la thing to notify is that, when hman reported the problem, the related tiki branch was 18.x. According to that was adviced by Marc and my supervisor Adrien and that is said in the doc(where to commit), before fixing the problem I first checkd if the problem exist in tiki 18.x, 21.x, 23.x and 24.x and I found that the problem is not fixed in both of those versions, so I fixed in tiki 24 and when the merge request will be aprouved and merged, I will backport the commit in lower versions(23.x,21.x and then 18.x) to fix the problem in all of them.

For more details to the task: https://dev.tiki.org/item7425 and https://avan.tech/item71292