New: Darkmode

* New: Native Theme Engine

Co-Authored-By: Zak Saunders <thezak48@users.noreply.github.com>
(cherry picked from commit 2291f3e00eb2ff9268a0b2f49da8dde82ee13c04)

* Update CSS for themes

* Fixup CSS values

* Fixup remove duped Color-Impaired setting

* Fixup Link Colors

Co-Authored-By: Qstick <qstick@gmail.com>

frontend/src/Settings/MediaManagement/Naming/NamingOption.css

@@ -3,7 +3,7 @@
   align-items: center;
   flex-wrap: wrap;
   margin: 3px;
-  border: 1px solid $borderColor;
+  border: 1px solid var(--borderColor);
 
   &:hover {
     .token {
@@ -27,7 +27,7 @@
 .token {
   flex: 0 0 50%;
   padding: 6px 16px;
-  background-color: #eee;
+  background-color: var(--popoverTitleBackgroundColor);
   font-family: $monoSpaceFontFamily;
 }
 
@@ -37,7 +37,12 @@
   align-self: stretch;
   flex: 0 0 50%;
   padding: 6px 16px;
-  background-color: #ddd;
+  background-color: var(--popoverBodyBackgroundColor);
+
+  .footNote {
+    padding: 2px;
+    color: #aaa;
+  }
 }
 
 .lower {