Move logging config to main configuration file.

- Move the content of what was stored in log4rs.yml into the main config
  file, so that there is just one file to parse to get the complete
  configuration.
- Create the global switch `--home` to pass/overload the value for
  SEQUOIA_HOME in the configuration file.

src/main.rs

@@ -1,5 +1,6 @@
 //! Husk milter
 
+use anyhow;
 use std::process;
 use std::sync::{Arc, Mutex};
 
@@ -18,7 +19,7 @@ use daemon::Daemon;
 pub mod common;
 
 #[tokio::main]
-async fn main() {
+async fn main() -> anyhow::Result<()> {
     let args = CliArgs::parse();
 
     let config_file = match &args.config {
@@ -26,7 +27,8 @@ async fn main() {
         None => defaults::CONFIG_FILE_LOCATION
     };
 
-    let husk_config = match HuskConfig::load(config_file) {
+    // XXX: Improve the way cli parameters are passed into the configuration.
+    let husk_config = match HuskConfig::load(config_file, args.home.clone()) {
         Ok(config) => config,
         Err(e) => {
             eprintln!("{:?}", e);
@@ -34,14 +36,9 @@ async fn main() {
         }
     };
 
-    log4rs::init_file(husk_config.logfile_config(), Default::default()).unwrap();
-
-    log::info!("starting...");
+    husk_config.init_logging()?;
 
     let config_container: HuskConfigContainer = Arc::new(Mutex::new(husk_config));
 
-    if let Err(e) = commands::dispatch(args, config_container).await {
-        eprintln!("exit with {:?}", e);
-        // XXX: actually return an error code
-    }
+    commands::dispatch(args, config_container).await
 }