add Authentication

src/main/kotlin/ltd/hlaeja/library/accountRegistry/Authentication.kt

@@ -0,0 +1,12 @@
+package ltd.hlaeja.library.accountRegistry
+
+object Authentication {
+    data class Request(
+        val username: String,
+        val password: CharSequence,
+    )
+
+    data class Response(
+        val token: String,
+    )
+}