CB-7486 - Remove StatusBarBackgroundColor intial preference (black background) so background will be initially transparent

This should not be a default ios setting:
<preference name="StatusBarBackgroundColor" value="#000000" />
It makes it impossible to unset the initial background color (for transparent backgrounds).  Instead just have the default as no background color (which will effectively be transparent), and then allow users to override that with a desired color.

Signed-off-by: Shazron Abdullah <shazron@apache.org>
CB-7549 - [StatusBar][iOS 8] Landscape issue

When starting an app in landscape mode in ios 8 and then calling StatusBar.overlaysWebView(false), the screen would be pushed down all the way.  Changing the orientation did not fix the issue, leaving the page pushed down the width of the device.

We found that excluding the changes above in ios 8 fixed the issue, although it's possible that this is hiding a landscape orientation bug in ios 8 that may get fixed later.

Signed-off-by: Shazron Abdullah <shazron@apache.org>