pypeline: allow arbitrary config objects

Allow the `configuration` field of a pipe in a pipeline yaml file to be
of any type. When constructing the pipe object, the object will be
re-serialized via `yaml.dump` before being passed to the constructor.

python/revng/pypeline/pipeline_parser.py

@@ -55,9 +55,16 @@ def parse_pipe(
             )
         bindings.append(container_decls[arg])
 
-    configuration = task.get("configuration", "")
+    configuration = task.get("configuration")
+    if configuration is None:
+        configuration_string = ""
+    elif isinstance(configuration, str):
+        configuration_string = configuration
+    else:
+        configuration_string = yaml.safe_dump(configuration)
+
     return PipelineNode(
-        task=pipe_type(configuration),
+        task=pipe_type(configuration_string),
         bindings=bindings,
     )
 

python/revng/pypeline/schema.yml

@@ -76,10 +76,11 @@ $defs:
         description: The name of the pipe.
         example: my_pipe
       configuration:
-        type: string
-        description: The static configuration for the pipe, if any.
-        default: ""
-        example: intel_asm=1
+        type: [string, object]
+        description: |
+          The static configuration for the pipe, if any. Can be either a string
+          or an object. If an object the content will be re-serialized in YAML
+          and passed to the pipe constructor as a string.
       arguments:
         $ref: "#/$defs/args"
         description: The names of the containers to pass to the pipe.