Consolidate UI configuration in one place, allowing it to be overridden from the server

ui/src/config.js

@@ -0,0 +1,20 @@
+const defaultConfig = {
+  firstTime: false,
+  baseURL: '',
+  loginBackgroundURL: 'https://source.unsplash.com/random/1600x900?music'
+}
+
+let config
+
+try {
+  const appConfig = JSON.parse(window.__APP_CONFIG__)
+
+  config = {
+    ...defaultConfig,
+    ...appConfig
+  }
+} catch (e) {
+  config = defaultConfig
+}
+
+export default config