Add example42-style pdns_recursor

[alvagante]

A pair of notes:

• Shouldn't this be part of a powerdns module? (Don't know the tool well, just wondering)
• I'm not so fond of placing directly inside the module subclasses specific for a monitoring tool, so I'm a bit dubious about the munin subclass, but since is an option, disabled by default, it may make sense.
• I've recently accepted a major change on the .gitmodule file that forces the use of relative paths for the git repos. For this reason I'll probably include in the .gitmodule the link to my fork of your module. Hope that doesn't bother you.
• Please feel free to place your name as the module's author. Credits to who deserves them.

[erik-smit]

1. PowerDNS Recursive Server and PowerDNS Authoritive Server are separate products. This module is not an 'recursive' implementation of PowerDNS. This module is an implementation of PowerDNS Recursive Server.
2. The alternate would be to create a behemoth Munin module, carrying plugins and configurations for everything it needs to support. Or to create a munin-companion-module for every single daemon, which would make the module-tree even more cluttered and unhierarchical than it already is. The current solution is easily managable for me and like you said, disabled by default it probably won't do any harm, while still providing benefit for my usecase.
3. Does not bother me.
4. Hm, that does make sense. I always forget that part, and when I think about it I don't want to grab out the editor, git, etc. just for some naming. Maybe make the module_clone tool grab the git.user/git.email to autofill these fields? If you're cool with that, I could pull request it.

[alvagante]

Sorry for late reply, just exited a quite busy period, maybe. I added your repo directly in 1c46b587ac56b764e1ccb2c7d37042b874385285 so it points to your github account.

A patch to the module_clone.sh script to fit username and email would be very appreciated, when possible.