refactor: removed 1.x client files

dev/config/postcss.config.js

@@ -0,0 +1,14 @@
+module.exports = {
+  plugins: {
+    'autoprefixer': {},
+    'cssnano': {
+      preset: ['default', {
+        discardComments: {
+          removeAll: true
+        }
+      }]
+    },
+    'postcss-flexbugs-fixes': {},
+    'postcss-flexibility': {}
+  }
+}