Move webmks console button to instance operations button mixin

[skateman]

The button_group('vm_access') defined in x_vm_cloud_center.rb overrides the same group created in the InstanceOperationsButtonGroupMixin that is being included just before. Therefore, the remote console button for OpenStack instances is missing. By moving the webmks console to the InstanceOperationsButtonGroupMixin and dropping the button_group the issue is fixed.

Before:

After:

@miq-bot add_label bug, toolbars
@miq-bot add_reviewer @mzazrivec

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1615796

[miq-bot]

Checked commit skateman@7482010 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 0 offenses detected
Everything looks fine. 🍰

[aufi]

Looks good 👍 thanks @skateman

[gildub]

This is the BZ tracker for Gaprindashvili:
https://bugzilla.redhat.com/show_bug.cgi?id=1622471

[gildub]

The back port won't work for Gaprindashvili because the line removed from app/helpers/application_helper/toolbar/x_vm_cloud_center.rb have to apply at a different part of the file.