Improvements on standalone node execution (#55)

## What ❔

Documented a guide on setting up and running a local consensus node,
along with a new Makefile containing commands for easy execution. Also
modifies the database directory path for each node.

## Why ❔

The README and the Makefile would streamline generating the
configuration for all nodes with a single command and simplify running
the desired node. About the modification for the database directory
path, it seems beneficial for running multiple nodes on a single
machine, especially for local testing. However, in the broader
architecture of the Test Framework, each node is expected to operate
within a distinct Docker container or a similar setup. In that context,
this change might not be useful.

node/tools/Makefile

@@ -0,0 +1,12 @@
+.PHONY: run-node node-configs clean
+IP?=127.0.0.1:3054
+
+run-node:
+	export RUST_LOG=INFO && cd node-configs/${IP} && cargo run -- --database ./database/${IP} 
+
+node-configs:
+	cargo run --bin localnet_config -- --input-addrs addresses.txt --output-dir node-configs
+
+clean:
+	rm -rf node-configs
+	rm -rf database

node/tools/README.md

@@ -0,0 +1,5 @@
+# Running a test node
+
+1. Generate a file named `addresses.txt` in the root directory of the tools crate, containing node addresses in the format `IP:PORT`, with each address on a separate line.
+2. Run `make node-configs`. This command will establish a directory named `node-configs` and create a folder for each address listed in the `.txt` file, providing the necessary configuration files for the respective node.
+3. Execute `make run-node IP=<NODE_IP>`. The default value for this command would be `127.0.0.1:3054`. Note that running this command will take control of the terminal.

node/tools/src/main.rs

@@ -51,8 +51,8 @@ async fn main() -> anyhow::Result<()> {
     fs::create_dir_all("logs/")?;
     let log_file = fs::File::create("logs/output.log")?;
 
-    // Create the logger for stdout. This will produce human-readable logs for
-    // all events of level INFO or higher.
+    // Create the logger for stdout. This will produce human-readable logs for ERROR events.
+    // To see logs for other events, set the RUST_LOG environment to the desired level.
     let stdout_log = tracing_subscriber::fmt::layer()
         .pretty()
         .with_ansi(std::env::var("NO_COLOR").is_err() && std::io::stdout().is_terminal())