Parameters added:
- influxdb_urls
- telegraf_db_name
- telegraf_agent_interval
- http_response_timeout

Global telegraf settings are now managed via ini_setting resources.
Settings for this module are moved from telegraf.conf to
telegraf.d/puppet_metrics_dashboard.conf. These changes allow configs other
than the ones for this module to be set while still allowing this module
to udpate its config.

Update .fixtures and metadata (fixes #18)

Also removed top scope references and replaced legacy facts

Thanks @genebean!

Prior to this commit yumrepo was not in the fixtures. As it was removed
out of core in 6.x, spec tests would fail with newer versions of puppet.

Prior to this commit, the module was using PDK 1.7.0 and some checks
were failing. This commit updates PDK to 1.8.0 to fix the checks.

Update to PDK 1.8.0, thanks @jarretlavallee !

This commit refactors the module to more closely follow the install >
config > service manifest layout. Parameters were removed on all
manifests except init.pp. All manifests now directly reference
parameters from the puppet_metrics_dashboard class. The greatly reduces
duplication of code and sets the module up in a way that it could easily
move from params.pp to data in module later.

The docs at the top of manifests also got updated to reflect that
puppet-strings expects both a summary and a description that is not
prefixed with the @summary tag. In many cases this means duplicate
info... that is an unfortunate shortcoming of puppet-strings :(

Tests were lightly updated to reflect that subclasses do not have
params. One test was moved form install_spec.rb to init_spec.rb as it
made more sense there.

This commit does two things:
- reorganizes tests to matche the way the module is laid out
- increases test coverage to 100%

Refactor to a more standard layout

We need to install bundle differently for lower Ruby versions following
the release of Bundle 2.0

CI fix

Adding a Vagrantfile to facilitate local testing

Updates repo url and key, as per:

  https://grafana.com/blog/2019/01/05/moving-to-packages.grafana.com/
  voxpupuli/puppet-grafana#150

(MODULES-8585) update grafana repos

Add postgresql metrics collection