Create notification area for JITMs on Sensei Home

[fjorgemota]

Depends on #5625. Create a notification area for JITMs (Just in Time Messages) on Sensei Home, pulling data from the backend API to detect what notice to show.

We will need to be able to show the updates (using rules for version and license checking) that we might have for Sensei Pro, to show to the user so we can "motivate" the user into keeping the license for Sensei Pro active.

We have code to include notices on the Sensei Home already, by using:

wp.data.dispatch( 'core/notices' ).createNotice(
        'warning', // Can be one of: success, info, warning, error.
        'Hey there, visit the Sensei website, now!', // Text string to display.
        {
            isDismissible: true, // Whether the user can dismiss the notice.
            // Any actions the user can perform.
            actions: [
                {
                    url: 'https://senseilms.com',
                    label: 'View site', variant: 'secondary'
                },
            ],
        }
    );

We need to check if it matches our styling and also integrate it with the backend API.