feat(reload/enable): add settings for services

[mdschmitt]

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, the defaults set in the code still produce the same behavior.

Related issues and/or pull requests

Fixes: #80

Describe the changes you're proposing

Add a config value to the pillar to allow for reload-instead-of-restart and/or not enabling services on boot.

Pillar / config required to test the proposed changes

Details added to pillar.example, basically

prometheus:
  pkg:
    component:
      prometheus:
       service:
         enable: false # to disable the prometheus service on boot
         reload: true # to reload prometheus on changes instead of restarting every time

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

[mdschmitt]

This implementation has a potential edge case that messes with correct functionality. If prometheus/config/file.sls changes runtime parameters in /etc/default/prometheus and reload is set to true via pillar, the removed/added flags will not be applied because the service is reloaded instead of restarted.