An action is defined by two things: an action name, and zero or more named arguments.
There is no built-in notion of a record-specific or column-specific action, but you may choose to define an argument such as ColumnName or RecordID in order to implement these.
Does not provide interface elements to call those actions.
Return a list of the actions handled by this action provider.
Used to identify the action later on through the $actionName parameter in handleAction.
There is no namespacing on these actions, so you need to ensure that they don't conflict with other components.