Add a `slash` subcommand to disable all commands

[Flame442]

What component of Red (cog, command, API) would you like to see improvements on?

Core

Describe the enhancement you're suggesting.

A command such as [p]slash clear or [p]slash disableall should be created which disables all currently enabled slash commands. Suggested by seifcume.

Anything else?

No response

[ibirothe]

Is this issue still open to work on?

[Flame442]

There is currently a PR open to address this issue.

[Akash29g]

Is this issue, still open?

[Flame442]

As previously mentioned, there is currently a PR open to address this issue.

[Kowlin]

I'll mail the next person asking that question an laminated image of the issue, and its status.