fix: user invite email not sending and null variables

- Add missing BullModule queue registration and BullBoardModule to UsersModule
- Add invitingUser to event payloads to track who sent the invite
- Fix incorrect global variable in SendInviteUsersMailMessage (__views_dir -> __images_dirname)
- Use invitingUser as fromUser instead of invited user in email
- Update processors to use BullMQ pattern

Fixes issues:
1. Email not sending due to missing queue/processor registration
2. Null variables in email (firstName/lastName) because fromUser was the invited user
3. Image attachment failing due to wrong path

packages/server/src/modules/UsersModule/subscribers/SyncSystemSendInvite.subscriber.ts

@@ -33,7 +33,7 @@ export class SyncSystemSendInviteSubscriber {
    * @param {IUserInvitedEventPayload} payload -
    */
   @OnEvent(events.inviteUser.sendInvite)
-  async syncSendInviteSystem({ inviteToken, user }: IUserInvitedEventPayload) {
+  async syncSendInviteSystem({ inviteToken, user, invitingUser }: IUserInvitedEventPayload) {
     const authorizedUser = await this.tenancyContext.getSystemUser();
     const tenantId = authorizedUser.tenantId;
 
@@ -63,6 +63,7 @@ export class SyncSystemSendInviteSubscriber {
       {
         invite,
         user,
+        invitingUser,
       } as IUserInviteTenantSyncedEventPayload,
     );
   }