fix: rename utils.scss to themeUtils.scss

Author: eshankvaish

src/css/application.scss

@@ -2,7 +2,7 @@
 @import './colorPalette.scss';
 @import './patternfly.scss';
 @import './normalize.scss';
-@import './utils.scss';
+@import './themeUtils.scss';
 @import './base.scss';
 @import './formulae.scss';
 @import './forms.scss';