add global auth state to redux store

[SKairinos]

When a user logs in/out, a state change does not occur. This means components, like the header, do not re-render to reflect the state change.

Add a state to the global store and dispatch:

• a login event when a login endpoint is called
• a logout endpoint when the logout endpoint is called

In addition, the useSessionMetadata() hook will need to be made aware of the state change that all components using the hook are re-rendered.