Node 12 (#11149)

* chore(node): upgrade to version 12

* update package-lock.json

* upgrade bcrypt

* upgrade node-sass

* update deps

* fix deprecation

* downgrade amplitude

* fix client side tests

* fix common and integration tests, upgrade mongoose

webpack/webpack.base.conf.js

@@ -60,7 +60,7 @@ const baseConfig = {
           }),
           postcss: [
             autoprefixer({
-              browsers: ['last 2 versions'],
+              overrideBrowserslist: ['last 2 versions'],
             }),
             postcssEasyImport(),
           ],