Ingest different DRS formats

This PR is a significant rewrite of how we handle DRS file paths to allow us to ingest paths of a few different known DRS formats.

This involved:

• creating a new crate to handle just loading the different DRS types
• changing ingestion to load the different types and then convert them to our metadata format
• fix some funky issues with data-dir not behaving how it should
  • I also made it optional so not having it means that all datasets are ingested

freva/src/drs/metadata/custom.rs

@@ -45,7 +45,7 @@ pub enum Error {
 /// variable
 /// ```
 ///
-/// Parts can be located in either the path (i.e. `/` delineated) or in the filename (`_` delineated). They can also be
+/// Parts can be located in either the path (`/` delineated) or in the filename (`_` delineated). They can also be
 /// pressent multiple times in both path and filename, if that is the case, the last instance will be the final value
 /// and all previous ones are discarded. This mapping is very simple so more advanced processing like splitting or
 /// joining sections is not supported.
@@ -57,7 +57,7 @@ pub struct ComponentConfig {
     /// The keys of the different path segments in the order they are expected to appear in the path. This does not
     /// include the file name which is always at the end so no `filename` part is necessary.
     pub parts_dir: Vec<String>,
-    /// Key ordering from parts of the file (separated by `_`)
+    /// Key ordering from parts of the file name
     pub parts_file_name: Vec<String>,
     /// Formatting of the time section of the file's name.
     ///