Being able to ping all roleless users

Problem

A lot of communities have some sort of onboarding procedure, and once you do you gain some role that nets you access to the server. However, if you're just a user passing by, you might just skim the server rules (or wherever this info is located), and miss the procedure.

Proposed solution

Add a new @roleless (better names are welcome) mention, similar to @everyone and @here in functionality. That way, moderators or whoever can ping the people without a role (during a mass influx, for example) and tell them all at the same time how to proceed.

Notes (optional)

• This mention should be off and completely unavailable by default. The server owner should have to actively enable it
• It should be restrictable using permissions the same way @everyone and @here are
• Under Notification Settings, it should fall under the same category as "Suppress @everyone and @here"

• In other places, this is usually (at least AFAIK) solved by having some bot assign a specific role to users who have just joined. This seems like a strange workaround. Having the functionality built-in seems like a better solution long-term.