feat(framework): Support custom dynamic asset paths

[vladitasev]

This change introduces the option to dynamically calculate the actual asset path of each asset at runtime.

Sample usage:

// Convert OpenUI5 asset paths to real paths
import { registerAssetPathMappingFunction } from "@ui5/webcomponents-base/dist/util/EffectiveAssetPath.js";
registerAssetPathMappingFunction(path => path.startsWith("sap/") ? sap.ui.require.toUrl(path) : path);

This feature would allow the UI5 Web Components build for OpenUI5 to generate OpenUI5-friendly paths.

Example:

	var ar = "sap/ui/webcomponents/thirdparty/_assets/messagebundle_ar.d20c665dc46a6f9b.json";
	var bg = "sap/ui/webcomponents/thirdparty/_assets/messagebundle_bg.38428028ff3b1869.json";
	var ca = "sap/ui/webcomponents/thirdparty/_assets/messagebundle_ca.c46423cc94896604.json";
	var cs = "sap/ui/webcomponents/thirdparty/_assets/messagebundle_cs.d9d68b2690954b4e.json";
	var da = "sap/ui/webcomponents/thirdparty/_assets/messagebundle_da.1189e997523b89f6.json";
	var de = "sap/ui/webcomponents/thirdparty/_assets/messagebundle_de.1edf86f620dd657a.json";

and then have these paths converted to URLs at runtime.

Note: the asset path mapping is applied independently of configured assetsPath. Both are rarely expected to be used at the same time.