Rename OpenDevin to OpenHands (#3472)

* Replace OpenDevin with OpenHands

* Update CONTRIBUTING.md

* Update README.md

* Update README.md

* update poetry lock; move opendevin folder to openhands

* fix env var

* revert image references in docs

* revert permissions

* revert permissions

---------

Co-authored-by: Xingyao Wang <xingyao6@illinois.edu>

openhands/core/message.py

@@ -0,0 +1,59 @@
+from enum import Enum
+
+from pydantic import BaseModel, Field, model_serializer
+from typing_extensions import Literal
+
+
+class ContentType(Enum):
+    TEXT = 'text'
+    IMAGE_URL = 'image_url'
+
+
+class Content(BaseModel):
+    type: ContentType
+
+    @model_serializer
+    def serialize_model(self):
+        raise NotImplementedError('Subclasses should implement this method.')
+
+
+class TextContent(Content):
+    type: ContentType = ContentType.TEXT
+    text: str
+
+    @model_serializer
+    def serialize_model(self):
+        return {'type': self.type.value, 'text': self.text}
+
+
+class ImageContent(Content):
+    type: ContentType = ContentType.IMAGE_URL
+    image_urls: list[str]
+
+    @model_serializer
+    def serialize_model(self):
+        images: list[dict[str, str | dict[str, str]]] = []
+        for url in self.image_urls:
+            images.append({'type': self.type.value, 'image_url': {'url': url}})
+        return images
+
+
+class Message(BaseModel):
+    role: Literal['user', 'system', 'assistant']
+    content: list[TextContent | ImageContent] = Field(default=list)
+
+    @property
+    def contains_image(self) -> bool:
+        return any(isinstance(content, ImageContent) for content in self.content)
+
+    @model_serializer
+    def serialize_model(self) -> dict:
+        content: list[dict[str, str | dict[str, str]]] = []
+
+        for item in self.content:
+            if isinstance(item, TextContent):
+                content.append(item.model_dump())
+            elif isinstance(item, ImageContent):
+                content.extend(item.model_dump())
+
+        return {'role': self.role, 'content': content}