Adds ToolEntity marker interface to consolidate ToolUser and ToolRole.
Changes workflow area in publishing widget to display WorkflowLog as a form so that it can be extended.
Adds ToolEntity#sendNotification for sending a notification to a tool user and changes ToolUser#notifyVia to be a set so that they can opt in for more than one notification type at a time.
Deprecates Content#addNotification and all related classes and methods since Record#beforeSave and #afterSave methods are better and more general hooks.
Cleans up tool user display in the UI.
Improves workflow area display in the publishing widget.
Changes ToolEntity#sendNotification to more generic #getUsers.
Adds an extra space between the workflow state and comment in the workflow area within publishing widget.
Adds WorkflowLogs.
Adds placeholder display to set/record field UI.