Read dimensions other than variable and region from external repo (…

…#415)

nomenclature/config.py

@@ -122,10 +122,12 @@ class DataStructureConfig(BaseModel):
 
     """
 
+    model: Optional[CodeListConfig] = Field(default_factory=CodeListConfig)
+    scenario: Optional[CodeListConfig] = Field(default_factory=CodeListConfig)
     region: Optional[RegionCodeListConfig] = Field(default_factory=RegionCodeListConfig)
     variable: Optional[CodeListConfig] = Field(default_factory=CodeListConfig)
 
-    @field_validator("region", "variable", mode="before")
+    @field_validator("model", "scenario", "region", "variable", mode="before")
     @classmethod
     def add_dimension(cls, v, info: ValidationInfo):
         return {"dimension": info.field_name, **v}
@@ -134,7 +136,7 @@ def add_dimension(cls, v, info: ValidationInfo):
     def repos(self) -> dict[str, str]:
         return {
             dimension: getattr(self, dimension).repositories
-            for dimension in ("region", "variable")
+            for dimension in ("model", "scenario", "region", "variable")
             if getattr(self, dimension).repositories
         }