Make farming more flexible

- API {farming.register_hoe(), farming.register_plant()}
- Fertilities -> Plant only grow on soil with a fitting fertility, e.g. Wheat only grows on grassland, while cotton grows in deserts and grassland)
- New soil: Desert Sand
- Place seeds instead of plants

mods/farming/hoes.lua

@@ -0,0 +1,65 @@
+farming.register_hoe(":farming:hoe_wood", {
+	description = "Wooden Hoe",
+	inventory_image = "farming_tool_woodhoe.png",
+	max_uses = 30,
+	recipe = {
+		{"group:wood", "group:wood"},
+		{"", "group:stick"},
+		{"", "group:stick"},
+	}
+})
+
+farming.register_hoe(":farming:hoe_stone", {
+	description = "Stone Hoe",
+	inventory_image = "farming_tool_stonehoe.png",
+	max_uses = 90,
+	recipe = {
+		{"group:stone", "group:stone"},
+		{"", "group:stick"},
+		{"", "group:stick"},
+	}
+})
+
+farming.register_hoe(":farming:hoe_steel", {
+	description = "Steel Hoe",
+	inventory_image = "farming_tool_steelhoe.png",
+	max_uses = 200,
+	recipe = {
+		{"default:steel_ingot", "default:steel_ingot"},
+		{"", "group:stick"},
+		{"", "group:stick"},
+	}
+})
+
+farming.register_hoe(":farming:hoe_bronze", {
+	description = "Bronze Hoe",
+	inventory_image = "farming_tool_bronzehoe.png",
+	max_uses = 220,
+	recipe = {
+		{"default:bronze_ingot", "default:bronze_ingot"},
+		{"", "group:stick"},
+		{"", "group:stick"},
+	}
+})
+
+farming.register_hoe(":farming:hoe_mese", {
+	description = "Mese Hoe",
+	inventory_image = "farming_tool_mesehoe.png",
+	max_uses = 350,
+	recipe = {
+		{"default:mese_crystal", "default:mese_crystal"},
+		{"", "group:stick"},
+		{"", "group:stick"},
+	}
+})
+
+farming.register_hoe(":farming:hoe_diamond", {
+	description = "Diamond Hoe",
+	inventory_image = "farming_tool_diamondhoe.png",
+	max_uses = 500,
+	recipe = {
+		{"default:diamond", "default:diamond"},
+		{"", "group:stick"},
+		{"", "group:stick"},
+	}
+})