[Samba] SambaPosix tool

[Lars Hanke]

As announced several weeks ago, I'd share my tool to manage POSIX 
attributes in Samba4 AD LDAP.

You can find it at https://github.com/laotse/SambaPosix.

It works on my particular system, but it is largely untested and
weakly documented. But it supports a --dry-run mode, which produces
LDIF, if you don't trust the tool. ;)

I'll welcome contributions: tests, documentation, comments, extensions, 
fixes, ...

Have fun,
  - lars.