Add command line example for OSC startup

[oslovebug]

Fixes #796

[falkTX]

This is not how things work though, environment variables need to be passed before the program, not after.
So the example here does nothing, it works for you because the 2228 port is the default and CLI args are ignored at the moment.

It is still useful information to have, so I think with some minor changes it can be adapted and pushed into the docs and website too.

[falkTX]

I reworded it a bit and added as 7c589fe, thanks!