Function registration

registration(listenerId, fn): void
JMap.Application.Event.Extension.on.registration

This event is triggered after a user registers his own JMap Server NG extension.

The extension id is received as a param property of the event.
Parameters
- listenerId: string
  Your listener id (must be unique)
- fn: ((params) => void)
  Your listener function
  - - (params): void
    - Parameters
      params: JAppExtensionEventParams
      Returns void
Returns void
Example
```
// Triggered when a user register a new extension
JMap.Application.Event.Extension.on.registration("my-extension-listener", params => {
  const extensionId = params.extensionId
  console.info(`The following extension has been registered by the current user: "${extensionId}".`)
})
```