ensure a (simple) service resource exists for every runit_service

This ensures a `service` resource exists for all `runit_service`
resources. This should allow all recipes using the previous `runit_service` definition to continue operating.
leverage base Service provider actions when possible

This will ensure this provider behaves like the other service provider
and should bring things like why-run support along for free.
DRY up Runit-specific actions/signals code

These methods share the same logic, so let's just have them call a small
helper method.
search node attributes for sv_bin, sv_dir, service_dir

* sv_bin is now a runit_service resource attribute
* This approach allows the defaults for these attributes to be truly
platform-independent
* removes references to the node object in the provider and make
things more portable
spec fixes for recent refactors

The methods that return the helper resources are now private so specs
have to access them with Object.send.
Ensure Chef::Mixin::ShellOut is available to the minitest test.
level-up the gitignore

Ensure we ignore Bundler's Gemfile.lock and some other usual suspects.
add a test for notifying regular service resource
update changelog, readme, for changes leveraging core provider
Merge branch 'leverage-core-provider'