Make footer links translatable (#1417)

## Description:

This PR makes the footer link labels ("Privacy Policy" and "Terms of
Service") translatable via the i18n system.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

## Please put your Discord username so you can be contacted if a bug or
regression is found:

aotumuri

resources/lang/en.json

@@ -21,7 +21,9 @@
     "instructions": "Instructions",
     "how_to_play": "How to Play",
     "advertise": "Advertise",
-    "wiki": "Wiki"
+    "wiki": "Wiki",
+    "privacy_policy": "Privacy Policy",
+    "terms_of_service": "Terms of Service"
   },
   "news": {
     "full_changelog": "See the complete change log",

src/client/index.html

@@ -332,10 +332,20 @@
               class="ml-2 mr-4"
             />
           </a>
-          <a href="/privacy-policy.html" class="t-link" target="_blank">
+          <a
+            href="/privacy-policy.html"
+            data-i18n="main.privacy_policy"
+            class="t-link"
+            target="_blank"
+          >
             Privacy Policy
           </a>
-          <a href="/terms-of-service.html" class="t-link" target="_blank">
+          <a
+            href="/terms-of-service.html"
+            data-i18n="main.terms_of_service"
+            class="t-link"
+            target="_blank"
+          >
             Terms of Service
           </a>
           <p style="text-align: center">