Enums properly defined and nothing broke

[truffer11]

Pull Request Template

**Fixes issue #5 **

What was changed?

• Made the 5 status types into enums and created a "constants" folder under client-app/src.
• Replaced several handlings of statuses to work with the enums.

Why was it changed?

• The statuses were changed to enums for consistency, avoids typo errors, and allows for easy access.

How was it changed?

• A new folder named "constants" was created and a file "Enums.js" was created within that folder. Enums.js currently defines the 5 status types for our project as the JavaScript version of enums. There is also an export line at the end for ease of access.
• References to an item's status in DonatedItemsList.js and StatusDisplayPage.js have been switched to enums.

[miabu-pashh]

The overall use of enums is useful here for the user for proper abstraction, ensure immutability, which is a good practice for maintaining consistent item status values across the application. This helps prevent accidental modifications of the status values, ensuring the integrity of the data.
It might be beneficial to define this as an enum for better type safety.

[Anjali0407-git]

@truffer11 delete this file. All the app code should be within src/

[Anjali0407-git]

@truffer11 Can you please rename the file toEnums.ts. .ts is a typescript extension. Typescript has enum datatype (which is not there in javascript) which is very useful in our case.

[Anjali0407-git]

@truffer11 You can replace with enums in this file also.