Also optimize a few textures a tiny bit.

* Dutch "locale" file

* Add translation for "Copper Rail"

See https://pre-commit.com/ for more information.

See https://editorconfig.org/ for more information.

Hoes crafted from "rare" materials were deprecated in
https://github.com/minetest/minetest_game/commit/9c459e77ac943f10c74de3bdd420e07a2b8bb56f.

Hoes are still available in existing worlds, but they cannot
be crafted anymore.

This closes #29.

This closes #30.

- Update pre-commit hooks to 2.1.0

This addresses #9.

The legacy `depends.txt` and `description.txt` files are no longer
needed since Minetest 5.0.0 or later will read everything from
`mod.conf`.

This raises the minimum supported Minetest version to 5.0.0.

This makes them behave similarly to default rails.

Commands used:

- `parallel optipng -o7 -zm1-9 -strip all ::: **/*.png`
- `parallel advpng -z4 -i5000 ::: **/*.png`

- [mod frame](https://github.com/minetest-mods/frame)

* Add toolranks support

* Update the changelog for `toolranks` support

This is no longer required thanks to `mod.conf`.

* Translation using MT5 translation api

Fix #36

* Add hoe to french translation