coreos-download: clean up AWS cloud launchable regions
This changes cleans up AWS cloud launchable regions such that by default
only us-east-1 is displayed and only display other regions through selection
of target region in region dropdown list.
Additional changes include updating the "View Releases" button to link to
corresponding stream in release note page instead of to default stable stream,
and formatting the js files.
Signed-off-by: Allen Bai <abai@redhat.com>