[WIP] -Added code to show list of domain overrides for instances.

- Added list of Domain overrides by priority, items in the list are clickable links to a domain containing instance override.

@gmcculloug @mkanoor please review/test. This PR only show list of overrides for instances only. Will make another commit to show same list for classes and methods once we have back-end support for those.
This is a LOT of stuff to create for this test. Can we just stub out the ActiveRecord calls and return ```active_record_instance_double```s instead? Something like this:
```ruby

context "when the record exists" do
  let(:miq_ae_domain) { active_record_instance_double("MiqAeDomain", :name => "yet_another_fqname") }
  let(:miq_ae_instance) { active_record_instance_double("MiqAeInstance", :fqname => "fqname") }
  let(:override) { active_record_instance_double("MiqAeClass", :fqname => "another_fqname/fqname") }

  before do
    MiqAeInstance.stub(:find_by_id).with(123).and_return(miq_ae_instance)
    MiqAeClass.stub(: find_homonymic_instances_across_domains).with("fqname").and_return([override])
    MiqAeDomain.stub(:find_by_name).with("another_fqname").and_return(miq_ae_domain)
  end

  it "does stuff" do
    # assertions here about the assigned variables like you had.
  end
end
```