refactor: clean vue-cli vestiges

postcss.config.js

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

vue.config.js

@@ -1,26 +0,0 @@
-module.exports = {
-  pwa: {
-    name: 'Souvenir',
-    themeColor: '#8420a7',
-    msTileColor: '#212045',
-    appleMobileWebAppCapable: 'yes',
-    appleMobileWebAppStatusBarStyle: 'black',
-    workboxOptions: {
-      importWorkboxFrom: 'local'
-    }
-  },
-  parallel: false,
-  configureWebpack: {
-    module: {
-      rules: [
-        {
-          test: /\.worker\.js$/,
-          use: {
-            loader: 'worker-loader',
-            options: { inline: true }
-          }
-        }
-      ]
-    }
-  }
-}