feat: add create, update, delete test

[solomonng2001]

• Add create test api endpoint on backend
• test cases follows the following format

• number of pairs of input line and output lines
• input line (stdin)
• output line (stdout)
• ...repeat per input output pair

• Add update test api endpoint on backend
• Add delete test api endpoint on backend

POST /tests

To create a new test case, run the following command:

curl -X POST http://localhost:8083/tests \
-H "Content-Type: application/json" \
-d '{
"questionDocRefId": "sampleDocRefId123",
"questionTitle": "Sample Question Title",
"visibleTestCases": "2\nhello\nolleh\nHannah\nhannaH",
"hiddenTestCases": "2\nHannah\nhannaH\nabcdefg\ngfedcba"
}'

PUT /tests/{questionDocRefId}

To update an existing test case from an existing question, run the following command:

curl -X PUT http://localhost:8083/tests/{questionDocRefId} \
-H "Content-Type: application/json" \
-d '{
"visibleTestCases": "2\nhello\nolleh\nHannah\nhannaH",
"hiddenTestCases": "2\nHannah\nhannaH\nabcdefg\ngfedcba"
}'

DELETE /tests/{questionDocRefId}

To delete an existing test case from an existing question, run the following command:

curl -X DELETE http://localhost:8083/tests/{questionDocRefId} \
-H "Content-Type: application/json"

[tituschewxj]

Should we add update and delete for this also? Since we can also update and delete a question.

Also I noticed that there could be a slight issue if the input and output contains \n since it is being split by newlines, but this could be avoided by ensuring that the input/output is a single line on the frontend.

[tituschewxj]

LGTM!