Upgrade web server for OAuth connection process [add-on: google_assistant] (#1267)

* Update pages styling and better error handling

* Fix css

* Offload static folder to /usr/share/public

* Remove unnecessary os import

* Add a changelog and update the version

* Update google_assistant/config.json

* Update google_assistant/CHANGELOG.md

Co-authored-by: Pascal Vizeli <pascal.vizeli@syshack.ch>

google_assistant/rootfs/usr/share/public/css/style.css

@@ -0,0 +1,97 @@
+body {
+  font-family: 'Roboto', sans-serif;
+  background-color: #fafafa;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.card {
+  box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.14), 0 1px 5px 0 rgba(0, 0, 0, 0.12), 0 3px 1px -2px rgba(0, 0, 0, 0.2);
+  background-color: #ffffff;
+  color: #212121;
+  border-radius: 2px;
+  margin: 15px;
+  display: flex;
+  flex-direction: column;
+  justify-content: space-between;
+  width: 400px;
+  max-width: 90vw;
+}
+
+.card .card-content {
+  padding: 15px 25px;
+  border-bottom: 1px solid #bdbdbd;
+}
+
+.card .card-actions {
+  padding: 15px 25px;
+}
+
+h1 {
+  font-size: 24px;
+}
+
+img {
+  max-height: 60px;
+}
+
+ol {
+  margin: 28px 0 0 0;
+  padding: 0;
+  list-style-type: none;
+}
+
+ol li {
+  counter-increment: step-counter;
+  margin-bottom: 20px;
+  display: flex;
+  align-items: center;
+}
+
+ol li::before {
+  content: counter(step-counter);
+  margin-right: 5px;
+  padding: 3px 8px;
+  border-radius: 9999px;
+  border: 1px solid #bdbdbd;
+}
+
+input {
+  border: none;
+  box-sizing: border-box;
+  -moz-box-sizing: border-box;
+  -webkit-box-sizing: border-box;
+  border-bottom: 1px solid black;
+  font-size: 14px;
+  flex-grow: 1;
+  height: 30px;
+  width: 100%;
+  background: transparent;
+  outline: none;
+  transition: border-bottom 0.225s ease;
+}
+
+input:focus {
+  border-bottom: 2px solid black;
+}
+
+button {
+  font-size: 16px;
+  padding: 8px 10px;
+  background-color: transparent;
+  border: none;
+  color: #03a9f4;
+  cursor: pointer;
+  border-radius: 4px;
+  outline: none;
+  transition: background-color 0.225s ease;
+}
+
+button:hover {
+  background-color: #03a8f425;
+}
+
+button:active {
+  background-color: #03a8f44f;
+}