✨ (install PWA) Add install PWA app

src/components/InstallApp.vue

@@ -0,0 +1,29 @@
+<template>
+  <span class="install-app" v-if="showInstall">
+    <a @click="prompt" class="navbar-item">installer</a>
+    <pwa-install></pwa-install>
+  </span>
+</template>
+
+<script lang="ts">
+import { Component, Vue } from 'vue-property-decorator'
+import accountService from '@/services/AccountService'
+
+@Component
+export default class InstallApp extends Vue {
+  private showInstall: boolean = false
+  public mounted(): void {
+    window.addEventListener('beforeinstallprompt', async () => {
+      const accounts = await accountService.getAll(true)
+      this.showInstall = accounts.length > 0
+    })
+  }
+
+  public prompt(): void {
+    const pwaInstall = document.querySelector('pwa-install') as any
+    if (pwaInstall) {
+      pwaInstall.openPrompt()
+    }
+  }
+}
+</script>