Provide config action to set editor plugin configuration

Problem/Motivation

At the moment there is only 1 config action for editor (actually only for CKEditor5 in its corresponding core module) addItemToToolbar that adds the item to editor toolbar. In case this item has a configurable plugin, there is no action at the moment that allows to set the configuration for the plugin itself.

Proposed resolution

Expose setSettings method in Editor entity to allow to set settings with config actions. Maybe it is also better to allow to set the setting for only selected plugin. For this a new method will be needed for Editor entity of a config action in editor module.

Config action parameters would be as following:
1. config_name - as any config action, there should be a check, that this is editor entity
2. plugin name
3. plugin configuration