[AUR-391, AUR-393] Add Document and DocumentReader base (#6)

* Declare BaseComponent

* Brainstorming base class for LLM call

* Define base LLM

* Add tests

* Clean telemetry environment for accurate testing

* Fix README

* Fix typing

* add base document reader

* update test

* update requirements

* Cosmetic change

* update requirements

* reformat

---------

Co-authored-by: trducng <trungduc1992@gmail.com>

knowledgehub/documents/base.py

@@ -0,0 +1,22 @@
+from haystack.schema import Document as HaystackDocument
+from llama_index.schema import Document as BaseDocument
+
+SAMPLE_TEXT = "A sample Document from kotaemon"
+
+
+class Document(BaseDocument):
+    """Base document class, mostly inherited from Document class from llama-index"""
+
+    @classmethod
+    def example(cls) -> "Document":
+        document = Document(
+            text=SAMPLE_TEXT,
+            metadata={"filename": "README.md", "category": "codebase"},
+        )
+        return document
+
+    def to_haystack_format(self) -> HaystackDocument:
+        """Convert struct to Haystack document format."""
+        metadata = self.metadata or {}
+        text = self.text
+        return HaystackDocument(content=text, meta=metadata)