Feature Request: a run command to run a single request non-interactively

[shalpin]

The way I would like to work with posting is to set up a request using the TUI and env files and then when I am satisfied, run it via scripts passing the configured request name (and probably env file and collection directory).

I would like it if I could do something like:
posting run my_reqeust

This would not fire up the UI, but would instead run the request my_request from whatever collection is configured and send the output (server output and data mixed but perhaps with something to easily distinguish which is which) to stdout/err and exit (0 if response < 400, or non-0 if >= 400). It would be good to have an option (say --response-file) to define a file to send the response to so the server output and response could be separated. And perhaps a further option (say --append-response-file) to give the choice of overwriting an existing response file or appending to it (I wouldn't mind which would be the default).