Currently, to have ability to propagate peripherals, peripheral should have type modem.
This is little confusing in some cases, when peripheral are not actually a modem, but need to have this type, but not provide full API compatibility (for example, peripheral container, etc).

So, I guess, this api should be changed to allow different peripherals act like modems and propagate peripherals, but not to be modem itself.

Now that #963 is in, we're in a position to do this pretty easily - can have another peripheral type for things which provide modems.

That said, don't know if people have thoughts on a suitable type name? Some ideas:

• "peripheral_provider" is obviously accurate but slightly janky.
• "hub" also feels appropriate (both in the networking and "usb hub" sense), but maybe a little too non-descriptive?

Voting for hub, i guess