fix(resolving) Support domain names that start with a number.

[pjbakker]

Domains are allowed to start with numbers and are currently not resolved
because of the current simple regex.

The new regexes better cover the IPv4 and IPv6 address (with optional
netmask)

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?

No.

Related issues and/or pull requests

Describe the changes you're proposing

Currently the regex used for determining if a name has to be resolved only checks if it starts with a number or a colon.

For one this ignores the fact that IPv6 addresses can start with [a-f] as well, and it does not resolve domains that start with [0-9].

This fix replaces the current regex with two simplistic regexes that cover the IPv4 and IPv6 (with optional netmask).

Pillar / config required to test the proposed changes

Debug log showing how the proposed changes work

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