chore(stylelint): remove sass-lint/scss-lint in favor of stylelint

- remove scss-lint and sass-lint
- add stylelint and stylelint-order packages and configuration
- update all *.scss files to new syntax

fixes #14805

core/src/css/ionic.scss

@@ -2,7 +2,6 @@
 @import "./structure";
 @import "./typography";
 @import "./colors";
-
 @import "./padding";
 @import "./float-elements";
 @import "./text-alignment";