Replacing global themed sass-vars to css-vars (#4322)

* generating css-vars
* convert all global / theme sass vars to css vars with available default theme colors
* added missing colors to dark lens theme

src/renderer/components/editable-list/editable-list.scss

@@ -25,7 +25,7 @@
   .el-contents {
     display: flex;
     background-color: var(--colorVague);
-    color: $textColorSecondary;
+    color: var(--textColorSecondary);
     border-radius: $radius;
     flex-direction: column;