refactor: remove c- prefix and fix icon position

Author: mrholek

scss/_icon.scss

@@ -1,27 +1,28 @@
-.c-icon {
+.icon {
   display: inline-block;
   color: inherit;
   text-align: center;
+  vertical-align: -.125rem; // Fix the position of icon
   fill: currentColor;
-  &:not(.c-icon-c-s):not(.c-icon-custom-size) {
+  &:not(.icon-c-s):not(.icon-custom-size) {
     @include icon-size($icon-size-base);
 
     // TODO: create variable with a range
     @for $i from 2 through 9 {
-      &.c-icon-#{$i}xl {
+      &.icon-#{$i}xl {
         @include icon-size($i * ($icon-size-xl / 1.5));
       }
     }
 
-    &.c-icon-xl {
+    &.icon-xl {
       @include icon-size($icon-size-xl);
     }
 
-    &.c-icon-lg {
+    &.icon-lg {
       @include icon-size($icon-size-lg);
     }
 
-    &.c-icon-sm {
+    &.icon-sm {
       @include icon-size($icon-size-sm);
     }
   }