Add OCR, Background Removal, and PDF Editor features with tests

- Implemented OCR functionality using pytesseract for image and PDF text extraction.
- Added Background Removal service using rembg for image processing.
- Developed PDF Editor service for applying text annotations to PDF files.
- Created corresponding API routes for OCR, Background Removal, and PDF Editor.
- Added frontend components for OCR and Background Removal tools.
- Integrated feature flagging for new tools, ensuring they are disabled by default.
- Implemented comprehensive unit tests for OCR service, PDF editor, and background removal.
- Updated documentation to reflect new features and usage instructions.
- Added translations for new features in English, Arabic, and French.

backend/requirements.txt

@@ -21,6 +21,13 @@ PyPDF2>=3.0,<4.0
 reportlab>=4.0,<5.0
 pdf2image>=1.16,<2.0
 
+# OCR
+pytesseract>=0.3.10,<1.0
+
+# Background Removal
+rembg>=2.0,<3.0
+onnxruntime>=1.16,<2.0
+
 # AWS
 boto3>=1.34,<2.0