Add »link-type bridge« to denote a bridge without pre-configured ports

[Maximilian Wilhelm]

I'm thinking about adding link-type bridge to denote an interface is a bridge without having to rely on bridge-ports.

As bridge-ports none already is supported I'm unsure if this is a win yet it feels cleaner to me to denote this explicitly.

[Ariadne Conill]

Perhaps use bridge could work for this?