ImportHandler: UI for showing maxFileSize error on import

This commit is an integration to f4418149cb.

src/locales/en.json

@@ -143,5 +143,6 @@
   "pad.impexp.uploadFailed": "The upload failed, please try again",
   "pad.impexp.importfailed": "Import failed",
   "pad.impexp.copypaste": "Please copy paste",
-  "pad.impexp.exportdisabled": "Exporting as {{type}} format is disabled. Please contact your system administrator for details."
+  "pad.impexp.exportdisabled": "Exporting as {{type}} format is disabled. Please contact your system administrator for details.",
+  "pad.impexp.maxFileSize": "File too big. Contact your site administrator to increase the allowed file size for import"
 }

src/node/handler/ImportHandler.js

@@ -82,6 +82,12 @@ async function doImport(req, res, padId)
         if (err) {
           console.warn("Uploading Error: " + err.stack);
         }
+
+        // I hate doing indexOf here but I can't see anything to use...
+        if (err.stack.indexOf("maxFileSize") !== -1) {
+          reject("maxFileSize");
+        }
+
         reject("uploadFailed");
       }
       if(!files.file){ // might not be a graceful fix but it works
@@ -261,7 +267,7 @@ exports.doImport = function (req, res, padId)
   let status = "ok";
   doImport(req, res, padId).catch(err => {
     // check for known errors and replace the status
-    if (err == "uploadFailed" || err == "convertFailed" || err == "padHasData") {
+    if (err == "uploadFailed" || err == "convertFailed" || err == "padHasData" || err == "maxFileSize") {
       status = err;
     } else {
       throw err;

src/static/js/pad_impexp.js

@@ -111,6 +111,8 @@ var padimpexp = (function()
       msg = html10n.get("pad.impexp.uploadFailed");
     } else if(status === "padHasData"){
       msg = html10n.get("pad.impexp.padHasData");
+    } else if(status === "maxFileSize"){
+      msg = html10n.get("pad.impexp.maxFileSize");
     }
 
     function showError(fade)