Option to turn off watchdog feature

[FilipTokarski]

As in the title. In our React integration it is possible to turn off watchdog with disableWatchdog property:

• https://ckeditor.com/docs/ckeditor5/latest/getting-started/installation/self-hosted/react/react-default-npm.html#component-properties

This is a request to introduce similar option in Angular integration.

[marburek]

Implemented in #520