Persist node logs (#36)

* Persist node logs

* Fix clippy lints

* Delete the node's db on shutdown but persist logs

* Fix tests

* Separate stdout and stderr and use more consts.

* More consistent handling of open options

* Revert the use of subprocess

* Remove outdated comment

* Flush the log files on drop

* Rename `log_files` -> `logs_file_to_flush`

crates/node/src/lib.rs

@@ -23,7 +23,7 @@ pub trait Node: EthereumNode {
     /// Prune the node instance and related data.
     ///
     /// Blocking until it's completely stopped.
-    fn shutdown(self) -> anyhow::Result<()>;
+    fn shutdown(&mut self) -> anyhow::Result<()>;
 
     /// Returns the nodes connection string.
     fn connection_string(&self) -> String;