Test at startup if /api/v1/ returns 401 status code.
If yes redirect to login page, else continue.
On login save credentials (username, password) in localStorage.
On every request we set credentials in header if present.
Fixes: https://github.com/ansible-community/ara-web/issues/1
Change-Id: I0f0b18b5590dec4ebfce32aa6519bb46fc8533f5
9e2feefb2e