[Suggestion] Change the "No permission" message when accessing a trade request link

[tincs]

In The Black Market, each trade thread has an associated trade request link (aka trade request URL). This link is usually accessed by clicking the "Send Trade Request" button but it can also be sent over external platforms (Discord, Facebook) or embedded in web pages.

Here's an example of such a link: https://www.elitepvpers.com/theblackmarket/traderequest/1-1

When an user that is not logged in clicks a trade request link this "No permission" message is displayed:

You don't have permission to access this page.

Here's a screenshot of the message:

To make the message helpful to new forum users, I suggest changing it:

1. Explain that trade requests can only be done by users that are logged in;
2. Add a form to directly log in with username and password;
3. Add links to register an account and reset the password.

For comparison here's the message displayed when you access the inbox without being logged in: