feat: allow clients to specify whether a call has video initially or not

[Amzd]

Couple of questions:

• Do I need to make cffi and rpc place_outgoing_call function backwards compatible?
• Is it ok to add headers the way I did?

[iequidoo]

Do I need to make cffi and rpc place_outgoing_call function backwards compatible?

Not sure here however. Let's wait for someone else's approval. The only thing i can say is that for testing Desktop backward compatibility is convenient -- no need to rebuild Desktop, but only Core.

[WofWca]

Do I need to make cffi and rpc place_outgoing_call function backwards compatible?

On Desktop specifically we're fine with not having backwards-compatibility. But maybe some bot developers would like that, IDK.
I think the way to do this is to define a new function, and keep the old one's signature as is. Thankfully it's just 3 lines long.

[Amzd]

maybe some bot developers would like that

Afaik bots are not placing calls, so I will keep it simple like this.

[WofWca]

The code looks sane at a glance.
Did not test.

About the more high-level stuff, such as the introduction of a new param I am not sure.