feat: add Icons plugin

* Change existing icons to React wrapper components

* Add `icons` plugin to expose Icon components to plugin system

* Create components that re-export Lock and Unlock components so they can be changed separately in Authorise top button and Authorise operation summary button

* Add new Lock and Unlock icons to `auth` plugin

---------

Co-authored-by: Vladimír Gorej <vladimir.gorej@smartbear.com>

src/style/_buttons.scss

@@ -99,12 +99,12 @@
     border: none;
     background: none;
 
-    &.locked
+    .locked
     {
         opacity: 1;
     }
 
-    &.unlocked
+    .unlocked
     {
         opacity: .4;
     }