add NamespaceIdentifier to Core API

Author: SpaceWalkerRS

libraries/core/src/main/java/net/ornithemc/osl/core/api/util/NamespacedIdentifier.java

@@ -0,0 +1,52 @@
+package net.ornithemc.osl.core.api.util;
+
+import java.util.Objects;
+
+public final class NamespacedIdentifier {
+
+	public static NamespacedIdentifier fromMinecraft(String identifier) {
+		return new NamespacedIdentifier("minecraft", identifier);
+	}
+
+	public static NamespacedIdentifier from(String namespace, String identifier) {
+		return new NamespacedIdentifier(namespace, identifier);
+	}
+
+	private final String namespace;
+	private final String identifier;
+
+	private NamespacedIdentifier(String namespace, String identifier) {
+		this.namespace = namespace;
+		this.identifier = identifier;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if (this == o) {
+			return true;
+		}
+		if (!(o instanceof NamespacedIdentifier)) {
+			return false;
+		}
+		NamespacedIdentifier id = (NamespacedIdentifier) o;
+		return namespace.equals(id.namespace) && identifier.equals(id.identifier);
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash(namespace, identifier);
+	}
+
+	@Override
+	public String toString() {
+		return namespace + ":" + identifier;
+	}
+
+	public String getNamespace() {
+		return namespace;
+	}
+
+	public String getIdentifier() {
+		return identifier;
+	}
+}