We had the same texts four times, with slight variations in the case of
the management section.
We're unifying them under the "verification" i18n namespace, since the
texts are about actions which can be done depending on whether users are
verified or not.
Note the names of the i18n keys aren't very consistent, since we use
"debates" in plural but "proposal" in singular. We're leaving it like
this so existing translations aren't affected.
Using the `_html` suffix automatically marks texts as HTML safe, so
doing so on sanitized texts is redundant.
Note flash texts are not sanitized the moment they are generated, but
are sanitized when displayed in the view.
Sometimes we're interpolating a link inside a translation, and marking
the whole translations as HTML safe.
However, some translations added by admins to the database or through
crowdin are not entirely under our control.
Although AFAIK crowdin checks for potential cross-site scripting
attacks, it's a good practice to sanitize parts of a string potentially
out of our control before marking the string as HTML safe.
