[Docs] Revamp documentation (#1010)

docs/components/data-sources/qna.mdx

@@ -0,0 +1,13 @@
+---
+title: '❓💬 Queston and answer pair'
+---
+
+QnA pair is a local data type. To supply your own QnA pair, use the data_type as `qna_pair` and enter a tuple. Eg:
+
+```python
+from embedchain import Pipeline as App
+
+app = App()
+
+app.add(("Question", "Answer"), data_type="qna_pair")
+```