Refactor token authentication to cookie/session-based auth instead

[charl3sj]

The currently implemented token-based per-request authentication has a high rate of failure within Hasiru Dala's slow network. This could be changed to session-based auth i.e. user signs into Google -> sends token to /login endpoint -> start user session and use JSESSIONID and CSRFTOKEN for subsequent authorisations.

TODOS:

• Create a /login endpoint which would start a user session based on GoogleId Token received from client
• Enable CSRF protection
• Make necessary changes in SecurityConfiguration and related files

[charl3sj]

Refer https://stackoverflow.com/a/46721527/11224994

[charl3sj]

Do only after they start using the system and someone is available to test.