Handle JWT token refreshing and verifying

[orzechdev]

I want to merge this change because... it shows a loading state when the token is refreshing due to token expiration or it is verifying when the application starts - all the token expiration and verification logic is delegated to the SDK, implemented in saleor/saleor-sdk#29 and saleor/saleor-sdk#30 respectively.

⚠️ To test if the functionality works make sure to have HTTPS connection on both frontend and backend and backend to have SameSite=None and Secure flags set in set-cookie header received from tokenCreate mutation (saleor/saleor/core/middleware.py) - testing with cross-site domains requires HTTPS and Secure flag set to mitigate network attacks https://web.dev/samesite-cookies-explained. Also make sure to have set saleor env JWT_EXPIRE=True and set expiration delta e.g. JWT_TTL_ACCESS="1 minutes".
In saleor/saleor/core/middleware.py:

def jwt_refresh_token_middleware(get_response):
    ...
    response.set_cookie(
        ...
        secure=True,
        samesite="None"
    )

⚠️ Before merge SDK dependency must be updated when changes with saleor/saleor-sdk#29 and saleor/saleor-sdk#30 will be released.

Screenshots

Pull Request Checklist

1. All visible strings are translated with proper context.
2. All data-formatting is locale-aware (dates, numbers, and so on).
3. The changes are tested.
4. The code is documented (docstrings, project documentation).
5. Changes are mentioned in the changelog.

Test Environment Config

API_URI=https://master.staging.saleor.rocks/graphql/

[patrys]

Task linked: CU-6a5vxt Storefront: use refresh Token to re-generate expired JWT token