Add variable to set name_format for auditd

[schurzi]

resolves #796

[schurzi]

@rndmh3ro WDYT? It makes sense to open up that configuration to better manage logs. Excerpt from the man page:

   name_format
          This option controls how computer node names  are  inserted  into  the  audit  event
          stream.  It has the following choices: none, hostname, fqd, numeric, and user.  None
          means that no computer name is inserted into the audit event.  hostname is the  name
          returned  by  the  gethostname syscall. The fqd means that it takes the hostname and
          resolves it with dns for a fully qualified domain name of that machine.  Numeric  is
          similar  to  fqd  except  it resolves the IP address of the machine. In order to use
          this option, you might want to test that 'hostname -i' or 'domainname -i' returns  a
          numeric  address.  Also,  this option is not recommended if dhcp is used because you
          could have different addresses over time for the same machine.   User  is  an  admin
          defined string from the name option. The default value is none.

[rndmh3ro]

The change itself is great, approved!

In some future I'd like to remove the whole audit-stuff though - it does not really harden anything..

[schurzi]

I already have a person in our team who has volunteered to add a audit role. My plan is to extract all audit related stuff in an extra role and also add some helpful base config.