Use JSON:API Menu Items by default

[Decipher]

Is your feature request related to a problem? Please describe.
The DruxtMenu module uses the default Drupal Menu items by default, but they don't support system and plugin menus.

As the Drupal Druxt module requires JSON:API Menu Items, the DruxtMenu module should default to use this data.

Describe the solution you'd like

• Use JSON:API Menu Items data by default

Describe alternatives you've considered
N/A

Additional context
The DruxtSite module already sets this by default:

druxt.js/packages/site/src/nuxtModule.js

Lines 20 to 23 in 2f2a7cc

	menu: {
	jsonApiMenuItems: true,
	...((this.options || {}).druxt || {}).menu,
	},

The same code could be used here:

druxt.js/packages/menu/src/nuxtModule.js

Lines 30 to 37 in 2f2a7cc

	const options = {
	baseUrl: moduleOptions.baseUrl,
	...(this.options || {}).druxt || {},
	menu: {
	...((this.options || {}).druxt || {}).menu,
	...moduleOptions,
	}
	}