add api to map cid to multiadress suffexed with cid on any node

[dzmitry-lahoda]

so if i have cid, i can map to adress to download from peer (via external proxy adress or other)

[alari]

Can you provide an example plz? With type definition if possible

[dzmitry-lahoda]

existing apis (so also hard to read these without examples of input out puts):

-- Download file `cid` from IPFS node `from` and save it to `node`
func get_from(node: PeerId, cid: CID, from: Multiaddr) -> IpfsGetResult 
... seems returns local path

-- Get externally available multiaddress of IPFS's HTTP RPC endpoint (usually on port 5001)
func get_external_api_multiaddr(node: PeerId) -> IpfsMultiaddrResult
.. not cid specific - need to merge somehow values - error prone. 

assuming above do not cover next:

--- gets download link via proxy for give CID
get_from_external_api_multiaddr(node: PeerId, cid: CID) -> IpfsMultiaddrResult
read it as part `IpfsFluence` path utility

[dzmitry-lahoda]

So I have CID, pass it to fluence, fluence returns me something, I plug that into ipfs js client -> it works. I do not really care what is inside.