Enable JavascriptCanOpenWindows and LocalStorageEnabled by default

Both QWebEnginePage::createWindow and QQuickWebEngineNewViewRequest
behave as if JavascriptCanOpenWindows was disabled by default, when
the application isn't handling new window signals.

LocalStorageEnabled should have no negative impact to be enabled
beside the used disk space, but is still less inconvenient than
cookies or disk cache, which are also enabled by default.

Change-Id: I3f5343c2410fac50bec08b386defe22baf3df440
Reviewed-by: Andras Becsi <andras.becsi@digia.com>