Role refactoring to address #11

[atosatto]

This PR contains some breaking changes to attempt fix PR #11.

• Removed the url installation method (in case, we still need a commit to remove it from the doc)
• Added actions to query the APT/YUM repositories to get the available pdns_recursor package version
• Configuring the pdns_recursor before actually installing it

Off course, this is open for discussion.

[atosatto]

Well, as discussed on IRC with @pieterlexis and @Habbie, I've replace in 7a372fa the awk shell trick to obtain the available pdns-recursor package list from the remote repos with custom modules miming the apt-cache madison command.

[atosatto]

@Habbie and @pieterlexis this PR is now completed.
It's a lot of stuff but I really would like to hear some feedbacks from you (and hopefully get you merge it).

[atosatto]

To test all the stuff (if you have Vagrant and Virtualbox installed) and see how it does work:

# Install molecule
$ pip install molecule

# Get the available test platforms
$ molecule list
AVAILABLE PLATFORMS
centos-7       (default)
ubuntu-xenial
debian-jessie

# Test on a platform (eg. ubuntu-xenial)
$ molecule converge --platform=ubuntu-xenial

# Cleanup everything
$ molecule destroy

The executed test playbook is playbook.yml in the project root directory.

[pieterlexis]

👍 lgtm!