Added a new binary, accounts_manager.

- Updated main Cargo.toml file
 - Created a new readme & binary
 - Includes configuration options from the validator, which now has it's config as a library.

account_manager/src/main.rs

@@ -0,0 +1,58 @@
+use bls::Keypair;
+use clap::{App, Arg, SubCommand};
+use slog::{debug, info, o, Drain};
+use std::path::PathBuf;
+use validator_client::config::ValidatorClientConfig;
+
+fn main() {
+    // Logging
+    let decorator = slog_term::TermDecorator::new().build();
+    let drain = slog_term::CompactFormat::new(decorator).build().fuse();
+    let drain = slog_async::Async::new(drain).build().fuse();
+    let log = slog::Logger::root(drain, o!());
+
+    // CLI
+    let matches = App::new("Lighthouse Accounts Manager")
+        .version("0.0.1")
+        .author("Sigma Prime <contact@sigmaprime.io>")
+        .about("Eth 2.0 Accounts Manager")
+        .arg(
+            Arg::with_name("datadir")
+                .long("datadir")
+                .value_name("DIR")
+                .help("Data directory for keys and databases.")
+                .takes_value(true),
+        )
+        .subcommand(
+            SubCommand::with_name("generate")
+                .about("Generates a new validator private key")
+                .version("0.0.1")
+                .author("Sigma Prime <contact@sigmaprime.io>"),
+        )
+        .get_matches();
+
+    let config = ValidatorClientConfig::build_config(&matches)
+        .expect("Unable to build a configuration for the account manager.");
+
+    // Log configuration
+    info!(log, "";
+          "data_dir" => &config.data_dir.to_str());
+
+    match matches.subcommand() {
+        ("generate", Some(_gen_m)) => {
+            let keypair = Keypair::random();
+            let key_path: PathBuf = config
+                .save_key(&keypair)
+                .expect("Unable to save newly generated private key.");
+            debug!(
+                log,
+                "Keypair generated {:?}, saved to: {:?}",
+                keypair.identifier(),
+                key_path.to_string_lossy()
+            );
+        }
+        _ => panic!(
+            "The account manager must be run with a subcommand. See help for more information."
+        ),
+    }
+}