chore(i): add third-party widget styles folder

assets/scss/widgets/_index.scss

@@ -1,13 +1,9 @@
-@import 'cell-tooltip';
-@import 'cookieconsent';
+@import 'third-party';
 @import 'details';
 @import 'fixed-button';
-@import 'github-corner';
 @import 'icon';
 @import 'link-guard';
 @import 'mask';
 @import 'noscript-warning';
-@import 'post-chat';
 @import 'reading-progress';
 @import 'scrollbar';
-@import 'typeit';

assets/scss/widgets/third-party/_index.scss

@@ -0,0 +1,5 @@
+@import 'cell-tooltip';
+@import 'cookieconsent';
+@import 'github-corner';
+@import 'post-chat';
+@import 'typeit';