Add Conversion Host features

[djberg96]

Adds features for ConversionHosts in order to satisfy ManageIQ/manageiq-api#507 as part of the v2v effort.

Marked as a WIP for now until my fellow v2v compatriots can confirm this is correct.

[djberg96]

@martinpovolny I've nested it under Migrations, and I can see in the database that it's set the product feature parent as expected.

[miq-bot]

Checked commits https://github.com/djberg96/manageiq/compare/cdcdd7ec4f9f28e94da21f8053f8ca74512a7707~...182ca5c6bdbd7c09cc00ee64ebe5c5108f4c5f6f with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
0 files checked, 0 offenses detected
Everything looks fine. 👍

[martinpovolny]

I am going to rebase #18203 on top of this one. And that will be the point where the content of the RBAC tree under roles will be expected to be correct.

[simaishi]

Hammer backport details:

$ git log -1
commit ea2cfab07d0453dc8553b97daf81dae3486c452a
Author: Martin Povolny <mpovolny@redhat.com>
Date:   Thu Nov 15 17:12:10 2018 +0100

    Merge pull request #18190 from djberg96/add_conversion_host_roles
    
    Add Conversion Host features
    
    (cherry picked from commit 808a114c18fba6ffe35a816a4ec67fa7cf0c7d68)