MinPlatformPkg: Add SerialPortTerminalLib to suport Serial Terminal feature

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3014



1. Add SerialPortTerminalLib to MinPlatformPkg/Library.
2. Add SerialPortTerminalLib to BdsDxe driver, to add the serial device to
  ConIn and ConOut variables
3. Include SerialDxe and TerminalDxe to CoreDxeInclude.dsc and
  CoreUefiBootInclude.fdf.

Reviewed-by: Eric Dong <eric.dong@intel.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Heng Luo <heng.luo@intel.com>