Add option to read configuration from stdin

If configuration filename is a hyphen "-", we attempt to parse
the input from stdin. This makes it possible to modify configuration files
with linux command line tools and pipe the results to (for example)
"anemoi-dataset create". Both linux pipes and input redirection is supported.

cat config.yaml | anemoi-datasets create - test.zarr
anemoi-datasets create - test.zarr < config.yaml

We attempt to read the contents using the supported parsers in the following
order: yaml, json, toml.

If all parsers fail, an exception is raised.

src/anemoi/utils/config.py

@@ -205,6 +205,22 @@ def load_any_dict_format(path) -> dict:
         if path.endswith(".toml"):
             with open(path, "rb") as f:
                 return tomllib.load(f)
+
+        if path == "-":
+            import sys
+            config = sys.stdin.read()
+
+            parsers = [(yaml.safe_load, "yaml"), (json.loads, "json"), (tomllib.loads, "toml")]
+
+            for parser, parser_type in parsers:
+                try:
+                    LOG.debug(f"Trying {parser_type} parser for stdin")
+                    return parser(config)
+                except Exception as e:
+                    pass
+
+            raise ValueError(f"Failed to parse configuration from stdin")
+
     except (json.JSONDecodeError, yaml.YAMLError, tomllib.TOMLDecodeError) as e:
         LOG.warning(f"Failed to parse config file {path}", exc_info=e)
         raise ValueError(f"Failed to parse config file {path} [{e}]")