WASHINGTON (AP) — In an opening salvo against "Obamacare," President Donald Trump signed an executive order Friday night that appears aimed squarely at undoing the unpopular requirement that individuals carry insurance or face fines. [...] it directs them to grant waivers, exemptions and delays of provisions in the Affordable Care Act that would impose costs on states or individuals, potentially including the law's penalties on people who remain uninsured — a key provision. [...] GOP lawmakers in Congress have proposed an exemption for people in areas where only one insurer offers coverage — currently about a third of U.S.