Use udev for serial device enumeration on Linux

Device enumeration code has been lifted from
src/chrome/browser/extensions/api/serial and moved into src/device/serial.

The enumeration impl for Linux now uses udev to enumerate devices matching the
"tty" subsystem, rather than matching /dev node name patterns.

The Windows implementation remains effectively unchanged, and the Mac
implementation has had its /dev pattern filter relaxed to catch devices of the
more generic forms "/dev/tty.*" and "/dev/cu.*".

BUG=334698

Review URL: https://codereview.chromium.org/158063002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251218 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251218