Extend custom onAuthRequired handler with modal dialog to ask user to re-authenticate

[denysoblohin-okta]

Added custom onAuthRequired callback to both custom-login and okta-hosted-login samples with logic:

• If no previousAuthState, it's app initialization phase -> redirect user to the login page
• Otherwise it's autoRenew process -> display modal dialog to ask the user to trigger the login process

This way we can break the auto login loop

Internal ref: OKTA-445785

Added @giomamaladze/ng2-semantic-ui component for SUI modal. This fork is most stable and recent, original ng2-semantic-ui project is abandoned, as well as official Semantic-UI-Angular which is for Angular 1