Sailfish OS 5.1 translation round

Context As usual, before a new Sailfish OS version gets released, contributors are asked to translate the new entries or updating existing ones. I am the "moderator" for French language, so that gives a good indication of what this new version will bring. This time, a lot of people helped translating, so I mostly had to validate or tweak a bit the translations, which took me roughly 90 minutes…