Add the ability to attach the TUI to modem73 running in headless mode.

[B08Z]

Hello,

I feel rude for asking so much of you.
I have been using Modem73 and specifically the RNS interface and its been really cool.

One thing that I think would be an enhancement would be to enable a user to start the modem73 in headless mode - normal operation when used with RNSD running on server say.

Then allow a user to 'attach' to a running instance.
So it might look like

modem73 -A (default: --host 127.0.0.1 --port 8001)

Or something like this.

I have used Screen to achieve a similar effect (run modem73 in the background but get access to the TUI)

Low priority. Thanks for all your hard work.

[RFnexus]

That's a great idea :)

I'll see what I can do for this