(PDOC-95) Properly group and display multiple provider defaultfors

[whopper]

Prior to this commit, strings did not properly handle providers
which had multiple related defaultfors. In code, these are written
as comma-separated constraints. This commit updates strings' puppet
provider handler, as well as the template which generates HTML for
defaultfor statements.

Note that it was necessary to make a breaking change to the JSON
schema to accomodate multiple AND'ed defaults. Previously, provider
defaults were contained in a single key-value map. Now, they are
contained in an array of key-value maps, which allows multiple
constraints to be associated with each other.

[whopper]

Here's a before and after for the systemd provider, which has the following defaults:

  defaultfor :osfamily => [:archlinux]
  defaultfor :osfamily => :redhat, :operatingsystemmajrelease => "7"
  defaultfor :osfamily => :redhat, :operatingsystem => :fedora
  defaultfor :osfamily => :suse
  defaultfor :operatingsystem => :debian, :operatingsystemmajrelease => "8"
  defaultfor :operatingsystem => :ubuntu, :operatingsystemmajrelease => ["15.04","15.10","16.04","16.10"]
  defaultfor :operatingsystem => :cumuluslinux, :operatingsystemmajrelease => ["3"]

Before:

After:

The JSON looks like:

      "defaults": [
        [
          [
            "osfamily",
            "[:archlinux]"
          ]
        ],
        [
          [
            "osfamily",
            "redhat"
          ],
          [
            "operatingsystemmajrelease",
            "7"
          ]
        ],
        [
          [
            "osfamily",
            "redhat"
          ],
          [
            "operatingsystem",
            "fedora"
          ]
        ],
        [
          [
            "osfamily",
            "suse"
          ]
        ],
        [
          [
            "operatingsystem",
            "debian"
          ],
          [
            "operatingsystemmajrelease",
            "8"
          ]
        ],
        [
          [
            "operatingsystem",
            "ubuntu"
          ],
          [
            "operatingsystemmajrelease",
            "[\"15.04\",\"15.10\",\"16.04\",\"16.10\"]"
          ]
        ],
        [
          [
            "operatingsystem",
            "cumuluslinux"
          ],
          [
            "operatingsystemmajrelease",
            "[\"3\"]"
          ]
        ]
      ],

[peterhuene]

👍

[peterhuene]

Question though: is defaultfor osfamily: 'RedHat', osfamily: 'Gentoo' valid with respect to Puppet? That is to say, should it be an array of key-value pairs rather than a map for storing this data?

[whopper]

@peterhuene defaultfor osfamily: 'RedHat', osfamily: 'Gentoo' would be a conflicting defaultfor and would make the provider not the default of anything.

[whopper]

@peterhuene updated to use list of lists and verified the case of defaultfor osfamily: 'RedHat', osfamily: 'Gentoo' is displayed correctly (and that everything else still works)