Feature: Added Umb-Notifications

[loivsen]

Description

Added UmbNotifications!

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (minor updates related to the tooling or maintenance of the repository, does not impact compiled assets)

How to test?

    public void Handle(TemplateSavingNotification notification)
    {
        notification.Messages.Add(new EventMessage("Just some info", "Custom message", EventMessageType.Info));
        notification.Messages.Add(new EventMessage("Just an error", "Sending a notification with the error look", EventMessageType.Error));
        notification.Messages.Add(new EventMessage("Just a warning", "Another custom message", EventMessageType.Warning));
        notification.Messages.Add(new EventMessage("Just a default", "My default message", EventMessageType.Default));
        notification.Messages.Add(new EventMessage("Just a success", "Best color", EventMessageType.Success));

        notification.CancelOperation(
        new EventMessage(
            "Error",
            "This is my custom message: Operation not allowed.",
            EventMessageType.Error));

    }

Screenshots (if appropriate)

[iOvergaard]

LGTM!