Refactors custom action mixin method

[d-m-u]

We have a bunch of models that need the generic_custom_buttons method and it makes more sense to have that code in the mixin rather than duplicating it in all the models. This's 30 lines vs the almost four hundred, almost identical lines that the comparable PR requires.

Adds the custom actions mixin to all models that support custom buttons and changes mixin method to do something.

wip because needs UI components

Related to:
(Host:
eclarizio@8ca5858) [unnecessary if we're using this rather than https://github.com//pull/16369 because this includes the mixin and doesn't need the method or tests found in Erik's host PR]
eclarizio/manageiq-ui-classic@f7d05b4
eclarizio/manageiq-api@e637616 [unnecessary also cause it's covered in the linked api one, was just template for drew]

Everything else:
ManageIQ/manageiq-api#163

[d-m-u]

@miq-bot assign @gmcculloug
@miq-bot add_label enhancement

[gmcculloug]

@d-m-u With this change you can delete the generic_custom_buttons method in the Vm model as well.

https://github.com/ManageIQ/manageiq/blob/master/app/models/vm.rb#L116-L118

[gmcculloug]

@imtayadeway Wanted to get your thoughts on this change. Previously only 3 files used this mixin and 2 need to specify other classes (Service -> ServiceTemplate, GenericObject -> GenericObjectDefinition).

We want to support this on all object that are exposed to custom buttons (see list here) and now only those two exceptions above would need to override the generic_custom_buttons button.

Seems a much better approach then having to define generic_custom_buttons on all the classes that use it.

[imtayadeway]

This is good with me 👍

[gmcculloug]

Services get their custom buttons through the service_template (app/models/service.rb#L56) model which already includes this mixin. This is not needed.

[gmcculloug]

GenericObjects get their custom buttons through the generic_object_definition (app/models/generic_object.rb#L12-L18) model which already includes this mixin. This is not needed.

[miq-bot]

Checked commits d-m-u/manageiq@e5ea9ab~...029abc9 with ruby 2.3.3, rubocop 0.47.1, and haml-lint 0.20.0
27 files checked, 0 offenses detected
Everything looks fine. 🍰

[d-m-u]

@miq-bot add_label gaprindashvili/yes

[eclarizio]

Yeah, I'm good with just having to add in the mixin. As long as we don't have any weird cases where the CustomButton.buttons_for needs to pass in a slightly different class name, but then I guess we can just override it anyway.

[gmcculloug]

@eclarizio That is the case with ServiceTemplate and GenericObjectDefinition models, but as you state it can be handled by overriding the method in the model. The default mixin logic now handles the majority of models.

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit 141079d5b0a379cb10634493057f7beeaa6a9303
Author: Greg McCullough <gmccullo@redhat.com>
Date:   Wed Nov 1 11:54:20 2017 -0400

    Merge pull request #16371 from d-m-u/refactor_generic_custom_button_in_custom_action_mixin
    
    Refactors custom action mixin method
    (cherry picked from commit aea2443b4fa4e0bbfbdbc69f655df7d673d7a04c)