Multiple swarm addresses for offline support

[jimpick]

https://www.youtube.com/watch?v=XTgE2tA6Zhg

Copied from discussion here: https://github.com/ipfs/dynamic-data-and-capabilities/issues/59

[pgte]

Watch out that, as recently @satazor pointed out, js-ipfs doesn't boot up if one of the ws-star addresses fails to connect... :(

[parkan]

long discussion here: https://github.com/ipfs/js-ipfs/issues/1619

TLDR we need to use libp2p-websocket-star-multi for this to work, so we can:

• update peer-pad/examples/docs to use libp2p-websocket-star-multi
• encourage libp2p-websocket-star-multi be adopted as default in https://github.com/libp2p/js-libp2p-websocket-star/issues/61 (please +1 this!)