Add copy public id button

public/_locales/en/messages.json

@@ -161,6 +161,9 @@
     "setUsername": {
         "message": "Set Username"
     },
+    "copyPublicID": {
+        "message": "Copy Public UserID"
+    },
     "discordAdvert": {
         "message": "Come join the official discord server to give suggestions and feedback!"
     },

public/popup.css

@@ -265,7 +265,7 @@ background-color:#ec1c1c;
   align-items: center;
 }
 
-.sbSlimButton, #additionalButtons>button, button#setUsernameButton, #submitUsername {
+.sbSlimButton, #additionalButtons>button, button#setUsernameButton, #submitUsername, #copyUserID {
   background: none;
   border: none;
   color: white;
@@ -341,6 +341,14 @@ label>p, #disableExtension>p, #usernameValue, #usernameElement > div > p,#sponso
   cursor: pointer;
 }
 
+#copyUserID {
+  width: 100%;
+}
+
+#setUsernameContainer {
+  display: flex;
+}
+
 #usernameElement > div, #sponsorTimesContributionsContainer > div {
   display: flex;
   flex-flow: column nowrap;

public/popup.html

@@ -90,6 +90,9 @@
               <button id="setUsernameButton" title="__MSG_setUsername__">
                 <img src="/icons/pencil.svg" alt="__MSG_setUsername__" width="16" height="16" id="sbPopupIconEdit">
               </button>
+              <button id="copyUserID" title="__MSG_copyPublicID__">
+                <img src="/icons/clipboard.svg" alt="__MSG_copyPublicID__" width="16" height="16" id="sbPopupIconCopyUserID">
+              </button>
             </div>
             <div id="setUsername" style="display: none">
               <div id="setUsernameStatusContainer" style="display: none">