Add legal and final strings (#1185)

* add legal and final strings

* removed unneeded suffixes from string ids

* removed unused strings and simplified string ids for vnext-only strings

* reword nostreams option

app/ui/intro.js

@@ -8,10 +8,10 @@ module.exports = function intro(state) {
     >
       <div class="flex flex-col justify-end h-full">
         <h1 class="font-bold">
-          ${state.translate('uploadPageHeader')}
+          ${state.translate('introTitle')}
         </h1>
         <p class="max-w-sm mt-2 pr-16 font-light leading-normal">
-          ${state.translate('uploadPageExplainer')}
+          ${state.translate('introDescription')}
         </p>
         <img class="intro" src="${assets.get('intro.svg')}" />
       </div>