feat: Added impl_path field to Config struct

- Also clarified error::Error enum

src/config/mod.rs

@@ -24,6 +24,9 @@ pub struct Config {
 
     /// If true, print to std{out/err}
     pub verbose: bool,
+
+    /// Path to implementation config file
+    pub impl_path: Option<PathBuf>,
 }
 
 impl Default for Config {
@@ -34,6 +37,7 @@ impl Default for Config {
             accounts_path: "accounts".into(),
             map: "map.toml".into(),
             verbose: true,
+            impl_path: None,
         }
     }
 }