Replace alert() with modal for ACP password reset

Some browsers (e.g. Chrome) don't allow copying text out of alert()
dialogs.

src/acp.js

@@ -139,7 +139,7 @@ function handleSetRank(user, data) {
     });
 }
 
-function handleResetPassword(user, data) {
+function handleResetPassword(user, data, ack) {
     var name = data.name;
     var email = data.email;
     if (typeof name !== "string" || typeof email !== "string") {
@@ -164,19 +164,14 @@ function handleResetPassword(user, data) {
             expire: expire
         }, function (err) {
             if (err) {
-                user.socket.emit("errMessage", {
+                ack && ack({ error: err });
-                    msg: err
-                });
                 return;
             }
 
             Logger.eventlog.log("[acp] " + eventUsername(user) + " initialized a " +
                                 "password recovery for " + name);
 
-            user.socket.emit("errMessage", {
+            ack && ack({ hash });
-                msg: "Reset link: " + Config.get("http.domain") +
-                     "/account/passwordrecover/" + hash
-            });
         });
     });
 }

www/js/acp.js

@@ -229,6 +229,20 @@ socket.on("acp-list-users", function (users) {
                     socket.emit("acp-reset-password", {
                         name: u.name,
                         email: u.email
+                    }, function (result) {
+                        if (result.error) {
+                            modalAlert({
+                                title: "Error",
+                                textContent: result.error
+                            });
+                        } else {
+                            var link = new URL("/account/passwordrecover/" + result.hash,
+                                    new URL(location));
+                            modalAlert({
+                                title: "Reset Link",
+                                textContent: link
+                            });
+                        }
                     });
                 }).appendTo(reset);
         }

www/js/util.js

@@ -2097,6 +2097,11 @@ function errDialog(err) {
  * I *promise* that one day I will actually split this file into submodules
  * -cal
  */
+
+/**
+ * modalAlert accepts options { title, textContent, htmlContent }
+ * All are optional
+ */
 function modalAlert(options) {
     if (typeof options !== "object" || options === null) {
         throw new Error("modalAlert() called without required parameter");