hiera_config improvements

[Dmitry Ilyin]

hiera_config is a resource designed to generate the configuratio file for hiera on the managed nodes.
Practice have shown that it's not flexible enough.
Plugin writers require following features:

* It should add elements for all enabled plugins
* It should add elements for every file in the plugins folder
* It should allow plugins to report additional hiera elements to be added to the hierarchy.
* There should be a way to add supplementary top and bottom layers

[Dmitry Ilyin (idv1985)]

https://review.openstack.org/#/c/361461/
https://review.openstack.org/#/c/361462/

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: stable/mitaka
Review: https://review.openstack.org/362478

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/361461
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=efe27d1c7e2a792a30e28a5e48fe5bbfb1cd552b
Submitter: Jenkins
Branch: master

commit efe27d1c7e2a792a30e28a5e48fe5bbfb1cd552b
Author: Dmitry Ilyin <email address hidden>
Date: Fri Aug 26 15:22:36 2016 -0500

    Refactoring of the hiera_config resource

    Additional features required by the plugin authors

    * Collect additional files from "plugins" directory.
    * Collect additional files from the enabled plugins in the metadata
    * Collect additional files from the "hiera" key of each plugin
      in the "plugins" section and "hiera" section of each plugin's
      metadata section.
    * Add top and buttom additional sets of elements.

    Related-Bug: 1618139
    Change-Id: I95c31b9f8133d48627afc620a9fe20dbd5cf9512

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/362478
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=a14dda72f7a48b4e122b358cbe200a5e94c70425
Submitter: Jenkins
Branch: stable/mitaka

commit a14dda72f7a48b4e122b358cbe200a5e94c70425
Author: Dmitry Ilyin <email address hidden>
Date: Fri Aug 26 15:22:36 2016 -0500

    Refactoring of the hiera_config resource

    Additional features required by the plugin authors

    * Collect additional files from "plugins" directory.
    * Collect additional files from the enabled plugins in the metadata
    * Collect additional files from the "hiera" key of each plugin
      in the "plugins" section and "hiera" section of each plugin's
      metadata section.
    * Add top and buttom additional sets of elements.

    Cherry picked from: efe27d1c7e2a792a30e28a5e48fe5bbfb1cd552b
    Related-Bug: 1618139
    Change-Id: I95c31b9f8133d48627afc620a9fe20dbd5cf9512

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/361462
Committed: https://git.openstack.org/cgit/openstack/fuel-library/commit/?id=78a276eb6c09ba59cfe07a8a848cb10d3cfe3455
Submitter: Jenkins
Branch: master

commit 78a276eb6c09ba59cfe07a8a848cb10d3cfe3455
Author: Dmitry Ilyin <email address hidden>
Date: Fri Aug 26 15:44:10 2016 -0500

    Use hiera_config on the fuel master

    * Use the hiera_config instead of the template
      on the Fuel master node the same way as it's used
      on all the managed nodes.

    Related-Bug: 1618139
    Change-Id: Iaaee3d0887647c65debb91a611ab09f9da6c671f

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/382103

[OpenStack Infra (hudson-openstack)]

Change abandoned by Dmitry Ilyin (<email address hidden>) on branch: master
Review: https://review.openstack.org/382103