Add Material Tags

This adds a bunch of useful and missing Tags to be able to identify items that
are related to each other by a trait.

Co-authored-by: Jake Potrebic <jake.m.potrebic@gmail.com>
Co-authored-by: Lena Kolb <lenakolb2204@gmail.com>
Co-authored-by: Layla Silbernberg <livsilbernberg@gmail.com>
Co-authored-by: Newwind <newwindserver@gmail.com>

paper-api/src/test/java/io/papermc/paper/EntityTagsTest.java

@@ -0,0 +1,21 @@
+package io.papermc.paper;
+
+import io.papermc.paper.tag.EntityTags;
+import java.util.logging.Level;
+import org.bukkit.Bukkit;
+import org.bukkit.support.AbstractTestingBase;
+import org.junit.jupiter.api.Test;
+
+public class EntityTagsTest extends AbstractTestingBase {
+
+    @Test
+    public void testInitialize() {
+        try {
+            EntityTags.HORSES.getValues();
+            assert true;
+        } catch (Throwable e) {
+            Bukkit.getLogger().log(Level.SEVERE, e.getMessage(), e);
+            assert false;
+        }
+    }
+}