feat(framework): detect dynamically loaded OpenUI5

[vladitasev]

OpenUI5Support allows OpenUI5 to be loaded second

Background

Until now, the assumption was always that OpenUI5 will be loaded in advance, so if it is not detected, UI5 Web Components will never check for it later

Issues

• patchPopup and patchPatcher are not called on dynamically loaded OpenUI5 instances
• features such as F6Navigation don't work as expected if OpenUI5 is loaded second
• changing the theme for OpenUI5 does not reflect in UI5 Web Components

Improvements

• the OpenUI5 onInit hook is used
• patchPopup and patchPatcher are executed a.s.a.p. after OpenUI5 is loaded so that any popups open from OpenUI5 will not glitch
• the configuration is not synchronized: when OpenUI5 loads first (classic scenario) UI5 Web Components take its configuration and use it, however if UI5 Web Components is loaded first, and only then OpenUI5, it is up to the app to initialize OpenUI5 with the same settings as UI5 Web Components for consistency.
• if the theme is changed after OpenUI5 is loaded, the "OpenUI5 CSS Variables" detection will now succeed and UI5 Web Components will delete the adopted stylesheet and let OpenUI5 provide variables
• after OpenUI5 is loaded, it takes over once again responsibility for setting the theme and UI5 Web Components will listen for the OpenUI5 theme change event. Same for F6Navigation.