add PasswordInput component

packages/password-input/index.vue

@@ -0,0 +1,43 @@
+<template>
+  <div class="van-password-input">
+    <ul class="van-password-input__security van-hairline--surround" @touchstart.stop="$emit('focus')">
+      <li v-for="visibility in points" class="van-hairline">
+        <i :style="`visibility: ${visibility}`" />
+      </li>
+    </ul>
+    <div 
+      v-if="errorInfo || info" 
+      v-text="errorInfo || info" 
+      :class="errorInfo ? 'van-password-input__error-info' : 'van-password-input__info'"
+    />
+</div>
+</template>
+
+<script>
+export default {
+  name: 'van-password-input',
+
+  props: {
+    info: String,
+    errorInfo: String,
+    value: {
+      type: String,
+      default: ''
+    },
+    length: {
+      type: Number,
+      default: 6
+    }
+  },
+
+  computed: {
+    points() {
+      const arr = [];
+      for (let i = 0; i < this.length; i++) {
+        arr[i] = this.value[i] ? 'visible' : 'hidden';
+      }
+      return arr;
+    }
+  }
+};
+</script>