added Container.decryptWithPassword

src/commonMain/kotlin/net/sergeych/crypto2/Container.kt

@@ -321,6 +321,27 @@ sealed class Container {
             }.build()
     }
 
+    /**
+     * Decrypt the container with a password. It scans all key ids for
+     * these with `KDP` params, e.g., derived from password, and try to
+     * derive keys from the password and decrypt the container. If there are
+     * no derivable keys, or all of them failed to decrypt, returns null.
+     * It could be long operation if there are multiple derivable keys with heavy
+     * KDF. See [PBKD] and [KDF] for more.
+     *
+     * @return decrypted data or null
+     */
+    @Suppress("unused")
+    fun decryptWithPassword(password: String): UByteArray? {
+        for( id in this.keyIds ) {
+            id.kdp?.let { kdp ->
+                decryptWith(kdp.deriveKey(password))?.let { return it }
+            }
+        }
+        return null
+    }
+
+
     companion object {
 
         /**