Tests/login urls

[nifedara]

What does this PR do?

Adds login URLs tests 🎉

• I added tests for login url, callback url, and me url
• Contributes to resolving this issue: Implement Backend Test Cases for fAIr hotosm/fAIr#229

Consideration?

• Although coverage didn't pick this as something to test, I added tests for this(URL) as it as it is essential to have
• I used Black formatter
• I didn't add coverage to the requirement file. So to check coverage, you have to install it yourself:
  • pip install coverage

How to test?

• Clone this repo
• Follow the installation guide
• run docker exec -it api bash to run the following commands in the container:
  • coverage run --omit='*/usr/*' manage.py test tests.test_urls
  • or just coverage run manage.py test tests.test_urls
  • coverage report (to see a report of the test coverage)