Notifications: Cleaned up mails, added debounce for updates

- Updated mail notification design to be a bit prettier, and extracted
  text to new lang file for translation.
- Added debounce logic for page update notifications.
- Fixed watch options not being filtered to current user.

app/Activity/Notifications/Handlers/PageUpdateNotificationHandler.php

@@ -2,6 +2,8 @@
 
 namespace BookStack\Activity\Notifications\Handlers;
 
+use BookStack\Activity\ActivityType;
+use BookStack\Activity\Models\Activity;
 use BookStack\Activity\Models\Loggable;
 use BookStack\Activity\Notifications\Messages\PageUpdateNotification;
 use BookStack\Activity\Tools\EntityWatchers;
@@ -12,15 +14,31 @@ use BookStack\Users\Models\User;
 
 class PageUpdateNotificationHandler extends BaseNotificationHandler
 {
-    public function handle(string $activityType, Loggable|string $detail, User $user): void
+    public function handle(Activity $activity, Loggable|string $detail, User $user): void
     {
         if (!($detail instanceof Page)) {
             throw new \InvalidArgumentException("Detail for page update notifications must be a page");
         }
 
+        // Get last update from activity
+        $lastUpdate = $detail->activity()
+            ->where('type', '=', ActivityType::PAGE_UPDATE)
+            ->where('id', '!=', $activity->id)
+            ->latest('created_at')
+            ->first();
+
+        // Return if the same user has already updated the page in the last 15 mins
+        if ($lastUpdate && $lastUpdate->user_id === $user->id) {
+            if ($lastUpdate->created_at->gt(now()->subMinutes(15))) {
+                return;
+            }
+        }
+
+        // Get active watchers
         $watchers = new EntityWatchers($detail, WatchLevels::UPDATES);
         $watcherIds = $watchers->getWatcherUserIds();
 
+        // Add page owner if preferences allow
         if (!$watchers->isUserIgnoring($detail->owned_by) && $detail->ownedBy) {
             $userNotificationPrefs = new UserNotificationPreferences($detail->ownedBy);
             if ($userNotificationPrefs->notifyOnOwnPageChanges()) {
@@ -28,6 +46,6 @@ class PageUpdateNotificationHandler extends BaseNotificationHandler
             }
         }
 
-        $this->sendNotificationToUserIds(PageUpdateNotification::class, $watcherIds, $user, $detail);
+        $this->sendNotificationToUserIds(PageUpdateNotification::class, $watcherIds, $user, $detail, $detail);
     }
 }