plugin: support liquid network

[vincenzopalazzo]

Adding a very basic support for liquid network

[vincenzopalazzo]

looks like that rust bitcoin here is causing problem (from bitcoincore-rpc)

2023-12-17T00:52:03.980Z DEBUG   plugin-folgore_plugin: call get block by height
2023-12-17T00:52:03.980Z INFO    plugin-folgore_plugin: cln request {\"height\":2641160}
2023-12-17T00:52:04.621Z INFO    plugin-folgore_plugin: running into retry logic due a request failing. Time `4` waiting `60` secs
2023-12-17T00:52:04.621Z INFO    plugin-folgore_plugin: we try 4 times the request but the error persist
2023-12-17T00:52:04.622Z UNUSUAL plugin-folgore_plugin: client `esplora` return an error: code: -1, msg: Recovery strategy (TimeoutRety) fails: `code: -1, msg: BitcoinEncoding(Io(Error { kind: UnexpectedEof, message: \"failed to fill whole buffer\" }))`
/home/vincent/github/work/rust-btc/folgore/target/debug/folgore_plugin error: bad response to getrawblockbyheight (bad 'result' field: Parsing '{result:': object does not have member result), response was {"error":{"code":-1,"data":null,"message":"Recovery strategy (TimeoutRety) fails: `code: -1, msg: BitcoinEncoding(Io(Error { kind: UnexpectedEof, message: \"failed to fill whole buffer\" }))`"},"id":"cln:getrawblockbyheight#20","jsonrpc":"2.0"}

[vincenzopalazzo]

Assuming that this is correct, due that I am able to reproduce the following error on cln ElementsProject/lightning#6955 (comment)