[TIMOB-16650] Reworked web view

This PR includes the following tickets:
[TIMOB-16650](https://jira.appcelerator.org/browse/TIMOB-16647)
[TIMOB-16647](https://jira.appcelerator.org/browse/TIMOB-16647)
[TIMOB-16781](https://jira.appcelerator.org/browse/TIMOB-16781)
Also,
Reworked the UI.Button as well.
Layout engine.
Extended TiCore so UI components can be created in custom modules (used for Button and Webview in this case)