feat(framework): support theme dependent custom icon collections

[ilhan007]

The PR aims to add support for registering versioned/theme dependent custom icon collections.

Previously, one could register an icon collection (f.e. "my-icons") with the use of registerIconLoader and use it with the Icon web component:

<ui5-icon name="my-icons/home">

However, there is no API to register theme dependant version of the same icon, so that whenever the theme is changed the used SVGs are auto-switched behind the scenes.

Proposal
The markup remains the same, so that no changes will be required in the icon usage.

<ui5-icon name="my-icons/home">

-registerIconLoader now can be used to register additional second version (won't fail in case of multiple versions, but at the end the separation is "legacy" vs "sap_horizon" theme families) and use the newly supported field "themeFamily" to define in which themeFamily the icon collection should be used. If "themeFamily" is not present, by default it means in all themes (sap_belize_, sap_fiori_3_) other than "sap_horizon" theme families.

registerIconLoader("my-icons", () => {
	return Promise.resolve([{
		"collection": "my-legacy-icons",
		"packageName": "test",
		"data": {
			"mark": {
				
			},
		},
	},
	{
		"collection": "my-horizon-icons",
		"packageName": "test",
		"themeFamily": "sap_horizon",
		"data": {
			"mark": {
			
			},
		},
	}]);
});

*collection (my-legacy-icons, my-horizon-icons) is the name under we will internally store the icon collection

Flow
my-icons/home is set, if sap_fiori_3 is set, effectively show my-legacy-icons/home
my-icons/home is set, if sap_ horizon is set, effectively show my-horizon-icons/home

Fixes: #7312