fix(libp2p): sort addresses to dial as public, then relay

[achingbrain]

Adds a new default address sorter that sorts by:

1. public addresses
2. public relay addresess
3. private addresses
4. private relay addresses

Where they are equal, certified addresses take priority, otherwise the sort order is stable.

Refs: #2010

[maschad]

Looks good, I would just like to understand the rationale for prioritizing a certified private address over a public address, wouldn't it be less likely that the private address is routable?

[achingbrain]

I would just like to understand the rationale for prioritizing a certified private address over a public address, wouldn't it be less likely that the private address is routable?

It doesn't - take a look at the relevant test - public addresses are prioritised over private addresses, and certified addresses are prioritised over non-certified addresses but certified private addresses are not prioritised over public addresses.

[maschad]

It doesn't - take a look at the relevant test - public addresses are prioritised over private addresses, and certified addresses are prioritised over non-certified addresses but certified private addresses are not prioritised over public addresses.

What about this test? It seems to contradict that.

[achingbrain]

What about this test? It seems to contradict that.

That test only tests the certifiedAddressesFirst comparator, the defaultAddressSort comparator combines the publicAddressesFirst, certifiedAddressesFirst and circuitRelayAddressesLast comparators.

[maschad]

That's true, but I suppose if a consumer is using the certifiedAddressesFirst utility they wouldn't expect that order. Alternatively they could pass in their own custom address sorter.