Add openvpn package (#4156)

Add pre-built binaries

packages/openvpn.rb

+require 'package'
+
+class Openvpn < Package
+  description 'OpenVPN is an open source VPN daemon'
+  homepage 'https://openvpn.net/'
+  version '2.4.9'
+  compatibility 'all'
+  source_url 'https://swupdate.openvpn.org/community/releases/openvpn-2.4.9.tar.xz'
+  source_sha256 '641f3add8694b2ccc39fd4fd92554e4f089ad16a8db6d2b473ec284839a5ebe2'
+
+  binary_url ({
+    aarch64: 'https://dl.bintray.com/chromebrew/chromebrew/openvpn-2.4.9-chromeos-armv7l.tar.xz',
+     armv7l: 'https://dl.bintray.com/chromebrew/chromebrew/openvpn-2.4.9-chromeos-armv7l.tar.xz',
+       i686: 'https://dl.bintray.com/chromebrew/chromebrew/openvpn-2.4.9-chromeos-i686.tar.xz',
+     x86_64: 'https://dl.bintray.com/chromebrew/chromebrew/openvpn-2.4.9-chromeos-x86_64.tar.xz',
+  })
+  binary_sha256 ({
+    aarch64: '27e5efdb11c4d8b9af843d5e6cff5a6792dda5b09498f8781d6e094261869c59',
+     armv7l: '27e5efdb11c4d8b9af843d5e6cff5a6792dda5b09498f8781d6e094261869c59',
+       i686: '113d563f0881a1de9c742913ea32daca76a5e9da938c102245024b9072d80348',
+     x86_64: '02353189cfcc0fbe81ec8e13014d85dc67ce1a0c0c64ce2b6008345696d109c0',
+  })
+
+  depends_on 'libmbedtls'
+  depends_on 'lzo'
+
+  def self.build
+    system "./configure #{CREW_OPTIONS}"
+    system 'make'
+  end
+
+  def self.install
+    system 'make', "DESTDIR=#{CREW_DEST_DIR}", 'install'
+  end
+end