Refactor API and zone update handling

[tacerus]

PR progress checklist (to be filled in by reviewers)

• Changes to documentation are appropriate (or tick if not required)
• Changes to tests are appropriate (or tick if not required)
• Reviews completed

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What type of PR is this?

Primary type

• [build] Changes related to the build system
• [chore] Changes to the build process or auxiliary tools and libraries such as documentation generation
• [ci] Changes to the continuous integration configuration
• [feat] A new feature
• [fix] A bug fix
• [perf] A code change that improves performance
• [refactor] A code change that neither fixes a bug nor adds a feature
• [revert] A change used to revert a previous commit
• [style] Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc.)

Secondary type

• [docs] Documentation changes
• [test] Adding missing or correcting existing tests

Does this PR introduce a BREAKING CHANGE?

Yes.

Related issues and/or pull requests

Describe the changes you're proposing

1. Replace proprietary and unmaintained library with native HTTP calls
2. Support full zone metadata and rrset updates (additions, modifications, removals) with proper test=True/test=False handling and detailed diffs about changes utilizing the same data structure as the PowerDNS API itself

Pillar / config required to test the proposed changes

Pillar abstraction is not yet implemented. Hence a sample state file instead:

my_zone:
  powerdns.zone_present:
    - name: test2.pdns.home.lysergic.dev
    - kind: native
    - rrsets:
        - name: host5
          type: A
          ttl: 300
          records:
            - content: 127.0.0.3
            - content: 127.0.0.5
              disabled: True
        - name: host5
          type: AAAA
          ttl: 300
          records:
            - content: fe80::1
            - content: fe80::2
        - name: host6
          type: A
          ttl: 300
          records:
            - content: 127.0.0.3

Debug log showing how the proposed changes work

Exceeds GitHub maximum body size.

Documentation checklist

• Updated the README (e.g. Available states).
• Updated pillar.example.

Testing checklist

• Included in Kitchen (i.e. under state_top).
• Covered by new/existing tests (e.g. InSpec, Serverspec, etc.).
• Updated the relevant test pillar.

Additional context

This is a work in progress effort. I am sharing it already to gather potential early feedback and to learn whether such a big change is of interest to this project at all. The code still needs lots of cleanup, and it is of course lacking documentation and tests (for effective testing, the test suite will need to spin up a PowerDNS, which I am not yet sure how to integrate into the kitchen suite in this repository).

Most of the logic is around getting a usable diff for the changes to make for an experience as with other Salt states. Unfortunately, the PowerDNS API itself does not yet natively support operating in a dry-run mode with diff output.

The existing functions are for the most part refactored. Having a single zone_present() state function instead of separate rrset logic allows following of the upstream PowerDNS API data structure, making the state both easier to use for users (the same documentation as the upstream API can be followed) and easier to adapt in case of future changes to the upstream API.