[TIMOB-15296] Android: Support for window flags

This PR does a few things
1. Exposes a windowFlags property on WindowProxy for developers to specify extra flags
2. Refactors the Intent processing on BaseActivity so even JS Activities can support these falgs if specified
3. Removes support for deprecated light weight windows 
4. The first window launched treats exitOnClose set to true unless explicitly overridden by user

Test case is in [JIRA](https://jira.appcelerator.org/browse/TIMOB-15296)