- Improve french translation
Warnings:
- many untranslated new strings for German and Spanish translations (some help would be appreciated)
- Inner and Outer Stairs are still badly translated (since there is [no support for this in stairs api yet](https://github.com/minetest/minetest_game/issues/2582)).
Spawns in hot and dry desert, but requires water. This makes it a bit harder to
find, but where found, it can be more abundant.
If found in the middle of a desert, its presence indicates a water source below
the surface.
As an additional optional feature, dates (slowly) grow back after harvesting.
