[Refactor] Converge Pipeline and App classes (#1021)

Co-authored-by: Deven Patel <deven298@yahoo.com>

docs/components/data-sources/mdx.mdx

@@ -5,7 +5,7 @@ title: '📝 Mdx file'
 To add any `.mdx` file to your app, use the data_type (first argument to `.add()` method) as `mdx`. Note that this supports support mdx file present on machine, so this should be a file path. Eg:
 
 ```python
-from embedchain import Pipeline as App
+from embedchain import App
 
 app = App()
 app.add('path/to/file.mdx', data_type='mdx')