refactor: move advanced config to separate module

[mmalenic]

Closes #283

Refactor

• Configuration like regex-based storage locations has been moved to the advanced module inside config.
• Config doesn't use flatten anymore, which means that . needs to be used to separate nested values. Environment variables still use _.
• Renaming some values:
  • Local config is now called File.
  • Storage is called Backend. The tag type is now kind instead of backend.
  • C4GH config has keys.private and keys.public instead of private_key and recipient_public_key. The tag type for the key locations is also kind.
  • Resolvers are now Locations.
• File config only inherits scheme and authority values from the data_server now. It does not inherit the local_path.
• Data server doesn't use data prefix anymore, which makes the mapping between the initial request and URL tickets clearer.
• Removed use_data_server and data_server_path_prefix. use_data_server = false has been replaced with data_server = "None".

Fix

• Service info config can accept arbitrary json values.
• The "type" field in service info is not configurable.

Build

• Removed clippy from pre-commit as it can be quite slow.