Some toasts cleanup and reorg (#8748)

* Reorg

* Move animation into css file

* Update style comment

* Extract core component, use platform-specific wrappers

* Pull out platform specific styles

* Just move styles into Toast component itself

* Rename cleanup

* Update API

* Add duration optional prop

* Add some type docs

* add exp eased slide aniamtions

* Make toasts full width on mobile web

---------

Co-authored-by: Samuel Newman <mozzius@protonmail.com>

src/style.css

@@ -369,3 +369,23 @@ input[type='range'][orient='vertical']::-moz-range-thumb {
     transform: translateY(0);
   }
 }
+
+/*
+ * #/components/Toast/index.web.tsx
+ */
+@keyframes toastFadeIn {
+  from {
+    opacity: 0;
+  }
+  to {
+    opacity: 1;
+  }
+}
+@keyframes toastFadeOut {
+  from {
+    opacity: 1;
+  }
+  to {
+    opacity: 0;
+  }
+}