lib3h config option

[zippy]

PR summary

This PR implements the use of Lib3h configuration in core, and stubs out the ability to choose either lib3h or n3h as the p2p networking engine. See: lib3h:#43

Breaking Change: You must add type="n3h" for current config files to work. eg:
e.g. current n3h based configurations need to look something like like:

...

    [network]
    type="n3h"
    bootstrap_nodes = ["wss://192.168.0.11:64519/?a=hkYW7TrZUS1hy-i374iRu5VbZP1sSw2mLxP4TSe_YI1H2BJM3v_LgAQnpmWA_iR1W5k-8_UoA1BNjzBSUTVNDSIcz9UG0uaM"]
    n3h_persistence_path = "/Users/cnorris/.holochain/n3h_persistence"
    networking_config_file = "/Users/cnorris/.holochain/network_config.json"
    n3h_log_level = "d"

changelog

Please check one of the following, relating to the CHANGELOG-UNRELEASED.md

• this is a code change that effects some consumer (e.g. zome developers) of holochain core so it is added to the CHANGELOG-UNRELEASED.md (linked above), with the format - summary of change [PR#1234](https://github.com/holochain/holochain-rust/pull/1234)
• this is not a code change, or doesn't effect anyone outside holochain core development

[ddd-mtl]

lgtm

[willemolding]

The tests that are failing are these ones

can_get_all_links_of_any_tag_or_type
get_links_with_non_existent_tag_returns_nothing
get_links_with_non_existent_type_returns_nothing

Interestingly these are tests I have had issues with before when I didn't give the test instance a unique network name

test_instance(dna, netname)
                   ^^^^^^^^ - This was not unique

In that case they failed with the exact same timeout errors.

I am wondering if the network name is no longer being handled correctly resulting in conflicting in-memory networks.

[zippy]

That's exactly what I thought, and went and traced through the netname stuff but couldn't find things out of place. An now it looks like things pass. I can't see how your commit could have fixed it.

[willemolding]

I'm pretty sure it was using the json! macro incorrectly previously. To my knowledge you can't pass a formatted JSON string into it you have to use their macro/json style. I wonder if this meant that the netname was 'null' in every case