Request: Add new verb argument: {instance-name}

[AndydeCleyre]

Hello again!

I'm very excited to have finally noticed this new client-server socket stuff, thanks!

I'd like to try setting up an external directory jumper to integrate with a running broot instance (related: #247, #738) -- without quitting and relaunching broot, so that state and history is preserved as much as possible.

I think broot now has everything needed for this, as long as I only expect to have a single broot instance at a time (so that another process can use broot --send instance_name to a predictable instance_name). But I don't want to worry about multiple broot instances trying to use the same socket.

So I'm requesting that a new verb argument be added, so that my shell launcher function can generate some random name (or path? name, I think), launch broot with --listen random_name, and then a verb calling an external process can pass that random_name as an argument to that external process, so it can eventually send a message back to the corresponding socket.

If this is already possible in some way, or unnecessary for some reason, or just totally the wrong way to think about this problem, please let me know!

[AndydeCleyre]

I also wouldn't mind if broot could take care of generating the random socket name on its side, if it could be accessed via a verb argument like this.