reorganization of _examples and add some new examples such as iris+groupcache+mysql+docker

Former-commit-id: ed635ee95de7160cde11eaabc0c1dcb0e460a620

_examples/mvc/login-mvc-single-responsibility/public/css/site.css

@@ -0,0 +1,61 @@
+/* Bordered form */
+form {
+    border: 3px solid #f1f1f1;
+}
+
+/* Full-width inputs */
+input[type=text], input[type=password] {
+    width: 100%;
+    padding: 12px 20px;
+    margin: 8px 0;
+    display: inline-block;
+    border: 1px solid #ccc;
+    box-sizing: border-box;
+}
+
+/* Set a style for all buttons */
+button {
+    background-color: #4CAF50;
+    color: white;
+    padding: 14px 20px;
+    margin: 8px 0;
+    border: none;
+    cursor: pointer;
+    width: 100%;
+}
+
+/* Add a hover effect for buttons */
+button:hover {
+    opacity: 0.8;
+}
+
+/* Extra style for the cancel button (red) */
+.cancelbtn {
+    width: auto;
+    padding: 10px 18px;
+    background-color: #f44336;
+}
+
+/* Center the container */
+
+/* Add padding to containers */
+.container {
+    padding: 16px;
+}
+
+/* The "Forgot password" text */
+span.psw {
+    float: right;
+    padding-top: 16px;
+}
+
+/* Change styles for span and cancel button on extra small screens */
+@media screen and (max-width: 300px) {
+    span.psw {
+        display: block;
+        float: none;
+    }
+    .cancelbtn {
+        width: 100%;
+    }
+}