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/types/defaults.rs

@@ -1,3 +1,24 @@
 //! Defaults
 
 pub const CONFIG_FILE_LOCATION: &'static str = "/etc/husk/config.toml";
+
+/// Default logging configuration.
+pub const CONSOLE_LOGGING: &'static str = "
+[appenders.console]
+kind = \"console\"
+
+[appenders.console.encoder]
+pattern = \"{d(%Y-%m-%d %H:%M:%S)(local)} {h({l})} [{t}] {m}{n}\"
+
+[[appenders.console.filters]]
+kind = \"threshold\"
+level = \"debug\"
+
+[root]
+level = \"info\"
+appenders = [\"console\"]
+
+[loggers.\"husk\"]
+level = \"debug\"
+";
+