feat(util): Add md5 algorithm to util and use memcpy to replace some "=" value assignment

Use memcpy can reduce md5 cost time from 64us to 49us once, improve 23% performance

components/util/include/esp_md5.h

@@ -0,0 +1,59 @@
+// Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include <stdint.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+/**
+ * @brief          MD5 context structure
+ */
+typedef struct esp_md5_context {
+    uint32_t total[2];          /*!< number of bytes processed  */
+    uint32_t state[4];          /*!< intermediate digest state  */
+    uint8_t  buffer[64];        /*!< data block being processed */
+} esp_md5_context_t;
+
+/**
+ * @brief          MD5 context setup
+ * @param ctx      context to be initialized
+ * @return         0 if successful
+ */
+int esp_md5_init(esp_md5_context_t *ctx);
+
+/**
+ * @brief          MD5 process buffer
+ * @param ctx      MD5 context
+ * @param input    buffer holding the data
+ * @param ilen     length of the input data
+ * @return         0 if successful
+ */
+int esp_md5_update(esp_md5_context_t *ctx, const uint8_t *input, size_t ilen);
+
+/**
+ * @brief          MD5 final digest
+ * @param ctx      MD5 context
+ * @param output   MD5 checksum result
+ * @return         0 if successful
+ */
+int esp_md5_final(esp_md5_context_t *ctx, uint8_t output[16]);
+
+#ifdef __cplusplus
+}
+#endif
+