RuleBuilder's `events` property may not be necessary

[qomhmd]

I am building an app in which I only want to define rules as the whole editor is associated with an implicit event. However, the RuleEditor requires the events property. The event fields cannot be preset either (i.e., shown as disabled inputs).

In addition, an event like "Call the customer" cannot be represented by current module as it is a non-numeric function (true/false in this case).