We should add new function to plugin API, which behaves like onLoad but after dependencies are loaded

[wojtekw92]

When we are developing plugin sometimes we are using dependencies to external plugins especially when we are making for example child class, we have to clone prototypes.

In existing plugin API we have methods:

onLoad - that method runs once but plugins dependencies doesn't have to be loaded. That make this method not best choice for cloning prototype.

init, beforeInit, afterInit - those function are executed after dependencies are available, but also are executed for every editor instance. So there is also not the best place for this.

Sugested solution

In my opinion we should add method like onDependencyLoaded that will run once but after plugin dependencies are available.