Add support for 'ProLinux' OS target

[sophalHong]

ProLinux is an open source Linux operating system similar to Fedora, RHEL and CentOS.
Adding support for 'ProLinux' OS target is to enable oz-installer to allow template file to accept the value '{os.name} = ProLinux'
example: prolinux-8.1.tdl

<template>
  <name>ProLinux-8.1</name>
  <os>
    <name>ProLinux</name>
    <version>8</version>
    <arch>x86_64</arch>
    <install type='url'>
      <url>http://prolinux-repo.tmaxos.com/prolinux/8/os/x86_64/</url>
    </install>
    <rootpw>root</rootpw>
  </os>
</template>