Added Excel Import & Export Features

[SOUVIK-D10]

Issue Link

Closes #228

Changes Made

• Modified Food and Category repository
• New features
  1) Import:
  -It works in general flawlessly and imports the data in bulk.
  -BUG : As the t_category_master do not have direct link to menu or branch same Category name from different branches can merge.
  - The fields which require boolean value in general like is_veg or is_available supports a wide range of true values like Yes, Haa, haan, हो , 是, да, etc. for better customer experience
  2) Export: It works flawlessly and quickly exports the data in a .xlsx format. If no data is found it returns a empty template
  3) Template: Nothing special just provides the pre-generated template.
• Extra Features
  1) Generic Abstract Import and Export classes for excel kept for future use.

Type of Change

• [✅] New feature
• [❌] Bug fix
• [❌] Documentation update
• [✅] Code refactor (for discussed optimization)

Backend Testing (if applicable)

• [❌ ] Unit tests passed
• [✅] API endpoints tested locally with Postman/curl
• Test Cases:
  • Import: It works in general flawlessly but creates trouble with the above mentioned bug.
  • Export: It works flawlessly.
  • Template: It works flawlessly.

Functionality (if applicable)

• Put branch id add parameter and file in correct format(preferred use template). If you have data already in database for a branch put it's id to get its menu in excel format.

Additional Notes

• If Category name is used as category. The code auto corrects it on the run. Some minor errors are auto corrected.
• BUG : Two branch one category gets merged.
• Adding more features

[SOUVIK-D10]

Please suggest if any adjustments needed.