Update BrowserList configuration and usage. Closes preboot#108

- single place of configuration via .browserlistrc file
- up-to-date configuration aligned with @angular/cli generated one

Thanks!

.browserslistrc

@@ -1,7 +1,11 @@
-[production staging]
-> 1%
-ie 10
+# This file is currently used by autoprefixer to adjust CSS to support the below specified browsers
+# For additional information regarding the format and rule options, please see:
+# https://github.com/browserslist/browserslist#queries
+#
+# For IE 10-11 support, please remove 'not' from the last line of the file and adjust as needed
 
-[development]
-last 1 chrome version
-last 1 firefox version
+> 0.5%
+last 2 versions
+Firefox ESR
+not dead
+IE 10-11

postcss.config.js

@@ -1,7 +1,3 @@
 module.exports = {
-  plugins: {
-    autoprefixer: {
-      browsers: ['last 2 versions']
-    },
-  },
+  plugins: [require('autoprefixer')]
 };