Add support of ldk-node

[randomlogin]

This PR adds support of ldk-node to sim-ln.

Closes: #26

As ldk-node is not a daemon, before we start we parse the simulation config file and extract all ldk-nodes, build them and start. For that an additional chain source (bitcoind/esplora/electrum) is needed to start.

Before this PR can be merged, an update of used lighting libraries should be merged, as the current ldk-node has newer versions.

[carlaKC]

Before this PR can be merged, an update of used lighting libraries should be merged, as the current ldk-node has newer versions.

Feel free to bump this in a preparatory commit in this PR!

[randomlogin]

Initially I was trying to wire up ldk-node, which is not a daemon and I thought sim-ln could orchestrate ldk-node building, initialization. However it turned out that we want already running and funded nodes with opened channels, so this wasn't an option.

Added support of https://github.com/lightningdevkit/ldk-server, which is a reference daemon implementation with external API, it uses ldk-node internally.

Please note, that ldk-server has not yet been released, therefore a git reference and a revision is used in Cargo.toml

The configuration for ldk-server looks in the following way:

{
  "address": <ip:port or domain:port>,
  "api_key": <hex_encoded_api_key>,
  "cert": <path_to_tls_cert>,
  "network": <bitcoin|testnet|signet|regtest>
}

Please note that currently it's not possible to guess the network via RPC calls, that's why we need to provide it in the config. This might change in future.

[carlaKC]

Added support of https://github.com/lightningdevkit/ldk-server, which is a reference daemon implementation with external API, it uses ldk-node internally.
Please note, that ldk-server has not yet been released, therefore a git reference and a revision is used in Cargo.toml

Happy to go with server, I believe a release is coming soon ™️ !