Feature/detailed card

[TawfiqKhan]

What this PR does (required):

• loads the card details when a get request is made to the backend
• updated card model, added description, and deadline field which are optional. the tag field is also optional but has a default value
• updated the create card and update card route to reflect the model changes, added validation for date data

Screenshots / Videos (required):

Any information needed to test this feature (required):

• No way to check from the front end, I used postman to check the route.

Any issues with the current functionality (optional):

• N/A