Convert to PDK, fix log behavior with newer Puppet

[geoffdavis]

Convert the module to use the latest, greatest Puppet development kit.

Lint fix various puppet modules
Fix multiple issues with the ruby code, including some ambiguous assignments and comparisons that weren't evaluating in the right order on all versions of ruby.

This pull request is admittedly a big one, but there wasn't an easy way for me to check for various Ruby ambiguities without having a working rubocop or test framework around.

Unit tests now pass for Puppet 5, 6, and 7.

Fixes #43

[geoffdavis]

Still seeing the underlying bug with #43 on this updated branch, working on this some more.

[geoffdavis]

It turns out that the @property_hash for the resource is mostly empty, as if the type isn't populating it fully before passing it on to the provider.

From: /opt/puppetlabs/puppet/cache/lib/puppet/provider/quagga_logging/quagga.rb:78 quagga#flush:

    73:     commands << 'configure terminal'
    74:
    75:     if exists?
    76:
    77:       command = ['log']
 => 78:       require 'pry'; binding.pry
    79:       command << @property_hash[:name]
    80:
    81:       if @property_hash[:name] == 'file'
    82:         command << filename
    83:       end

[1] pry(#<Puppet::Type::Quagga_logging::ProviderQuagga>)> @property_hash
=> {:ensure=>:present}

[geoffdavis]

OK this is ready to merge. It turns out there were a number of issues, the biggest of which were:

• The type uses symbols for the name property, but the provider's instances method was using strings, so Puppet never saw an equivalence.
• Flushing based on the object's "dirty" state didn't appear to be implemented in this module, so I kludged that in based on another provider.