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

.docker/drs_config.toml

+[cmip5_name]
+root_dir = ".docker/data/cmip5"
+drs_format = "cmip5"
+
 [observations]
 root_dir = ".docker/data/obs"
 drs_format = "custom"
@@ -25,7 +29,3 @@ parts_file_name = [
 parts_time = "start_time-end_time"
 [observations.defaults]
 project = "observations"
-
-[cmip5_name]
-root_dir = ".docker/data/cmip5"
-drs_format = "cmip5"