Add auth header to API calls done after signin

[snehmatic]

Header to be added Authorization with value Bearer <access_token>
The access token would be generated by the server after a successful login. The login API's response looks like the below for now(might change later). We should get these tokens from the JSON, store them in local storage, and use them in the next API calls.

{
"refresh": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ0b2tlbl90eXBlIjoicmVmcmVzaCIsImV4cCI6MTcwOTkwMjk2NiwiaWF0IjoxNzA5ODE2NTY2LCJqdGkiOiIzMzVkNDg4ZTJiZTE0MGEzOTE5MjRlMWE5MmZiNGM2MCIsInVzZXJfaWQiOjIyfQ.yx7MJbrez_b7HbtY80vLRs7pmg_d0DHvkk2_SxYE_cY",
"access": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ0b2tlbl90eXBlIjoiYWNjZXNzIiwiZXhwIjoxNzA5ODE3NDY2LCJpYXQiOjE3MDk4MTY1NjYsImp0aSI6IjgxNGE5NGM4MzI2NTQ2YjBhZWNjMGJhM2Y4NzIxMDkzIiwidXNlcl9pZCI6MjJ9.LysyNiP6-7KD0FCVeTgBBqxDtI6BdR3qq434RkMrcHk"
}

JWT ref: https://auth0.com/docs/secure/tokens/json-web-tokens

[snehmatic]

dependent on pages that come after Sign In flow.