Also add French translation strings.

Using the new template, update all the translations. The French
translation has also been reviewed.

Updates all translations based on the new po/templates/luci-fw.pot.

This patch refreshes the translation files with the new strings and
updates the French translation.

Commit from LuCI Translation Portal by user keksdosenmann. 103 of 104 messages translated (0 fuzzy).

Commit from LuCI Translation Portal by user keksdosenmann. 393 of 414 messages translated (19 fuzzy).