rework mimetype config

 - users can now specify variables/classes that different
   extensions can "inherit" from, to prevent having to write the
   same mimetype multiple times

```
[extension]

[extension.png]
inherit = "some_predefined_class"
app_list = [
	{ command = "more_entries" } ]

1 files changed, 0 insertions, 23 deletions

diff --git a/src/config/mod.rs b/src/config/mod.rs
index 169e0ed..6cc4386 100644
--- a/src/config/mod.rs
+++ b/src/config/mod.rs
@@ -61,26 +61,3 @@ where
     };
     Some(config.flatten())
 }
-
-// parses a config file into its appropriate format
-fn parse_config_file<T>(filename: &str) -> Option<T>
-where
-    T: DeserializeOwned,
-{
-    let file_path = search_directories(filename, &CONFIG_HIERARCHY)?;
-    let file_contents = match fs::read_to_string(&file_path) {
-        Ok(content) => content,
-        Err(e) => {
-            eprintln!("Error reading {} file: {}", filename, e);
-            return None;
-        }
-    };
-
-    match toml::from_str::<T>(&file_contents) {
-        Ok(config) => Some(config),
-        Err(e) => {
-            eprintln!("Error parsing {} file: {}", filename, e);
-            None
-        }
-    }
-}