refactor: make components and logger optional

[paralin]

In previous releases of yamux the following was supported:

import { yamux } from '@chainsafe/libp2p-yamux'
const muxer = yamux()()

Now the following is required:

import { yamux } from '@chainsafe/libp2p-yamux'
const muxer = yamux()({logger: ...})

Adjust the code to support passing an empty logger and an empty Components.

Fixes #69

[paralin]

I give up on this and will just pass a stub Log from now on.