Add ability to load peers to use as bootstrap nodes

[cblgh]

To increase the resilience of using hyperswarm (e.g. networks being forcefully shut off, or booting into a specifically set up mesh network) it would be very useful if peers could somehow load in a list of IPs to use as introducers/bootstrap nodes for the network. Either that or just peers to connect to in general.

Similarly it would be very useful to export a list of the currently connected peers.

This has been discussed previously in

• toronto mesh would like to be able to pass in a list of ipv6 addresses granular network control cabal-club/cabal-cli#113 (comment) (related issue of supporting ipv6 in hyperswarm Support IPv6 hyperdht#1)

[mafintosh]

You can pass your own bootstrap list already using the dht options. Let me see if we expose nodes atm

[cblgh]

sweet! yeah exporting would be 👨‍🍳 👌

[mafintosh]

This landed in master with dht.getNodes, dht.addNodes

[cblgh]

heyyyy fantastic!