Refactor the long-hated users recipe into an HWRP

Ready for review:

* Refactor users recipe into an HWRP called opc_users which is compatible with EC11 and CS12
* Smarter logic to wait for HA master and then for erchef readyness, which helps this complete much faster
* No ponies were hurt in the making of this code
Can confirm these work:
```
echo -e "remote_file '/tmp/yay.rpm' do\n  source 'https://web-dl.packagecloud.io/chef/stable/packages/el/6/private-chef-11.2.5-1.el6.x86_64.rpm'\nend" | sudo chef-apply -s
Recipe: (chef-apply cookbook)::(chef-apply recipe)
  * remote_file[/tmp/yay.rpm] action create
    - update content in file /tmp/yay.rpm from e3b0c4 to a6c62f
    (file sizes exceed 10000000 bytes, diff output suppressed)
 /tmp  file /tmp/yay.rpm
/tmp/yay.rpm: RPM v3.0 bin i386/x86_64
```