Fix services to support user overrides from their gitlab.rb
Why:
The previous work matched what we were already doing with roles, but as we add roles for more things, having the user's gitlab.rb 'enable' settings overwritten due to a role they have enabled seems bad. (And also it made it so I couldn't switch to doing a enable_group(DEFAULT_GROUP)
in the other MR I am working on without overwriting users gitlab.rb settings.
Summary:
Adds a priority option to the disable/enable Services command
Defaults to writing service config to node.normal (The same place consume_attributes will)
Consume attributes happens after parsing so user's config will overwrite the normal attributes
A new 'enabled?' method was added to help deal with checking the various
places for whether a service is enabled or not. (Before consume_attributes
is run they can be in several places)