[web-src] Change player web interface build system to use vue-cli v3

Also bumps the player web interface version to 0.2.0.

Previously the build was based on the vue.js webpack template. The
template is deprecated and the recommended method for setting up a vue
application is vue-cli. This also changes the build from using webpack
v3 to webpack v4.

web-src/postcss.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+  plugins: {
+    autoprefixer: {}
+  }
+}