Implement Actions

# [CAAction](https://developer.apple.com/documentation/quartzcore/caaction)

```swift
func action(forKey: String) -> CAAction?
Returns the action object assigned to the specified key.

var actions: [String : CAAction]?
A dictionary containing layer actions.
```

> Action Identifiers
These constants are the predefined action identifiers used by action(forKey:), add(_:forKey:), defaultAction(forKey:), removeAnimation(forKey:), Layer Filters, and the CAAction protocol method run(forKey:object:arguments:).