Comment 9 for bug 1778098

Reviewed: https://review.openstack.org/591336
Committed: https://git.openstack.org/cgit/openstack/openstack-ansible-os_horizon/commit/?id=41291565f82d804aeebc15d0e1c0d719e00c37e1
Submitter: Zuul
Branch: stable/rocky

commit 41291565f82d804aeebc15d0e1c0d719e00c37e1
Author: Dmitriy R <email address hidden>
Date: Thu Jul 26 21:31:55 2018 +0300

    Implements custom theme distribution

    Adds key ``theme_src_archive`` to ``horizon_custom_themes``,
    which should point to archive with packed theme inside.
    Archive should be placed on the deployment host and it
    may be easily created by git-archive, or ansible git module.
    Structure inside archive should be as a standard theme,
    without any leading folders.

    Unarchive is used instead of synchronize with flat files,
    as synchronize establishes independent SSH connection
    and doesn't use nspawn or any other methods from
    custom ssh plugin and may case connection errors.
    Recursive copy has limitations on number of files inside of the
    directory. This limit is pretty high, but still it's a limit.

    This method differs from uploading custom files, as themes may
    have complex structure and include a lot of files.

    As a result, if ``horizon_custom_themes`` contains
    ``theme_src_archive`` key, theme will be distributed by role.

    Change-Id: Icbfff0793a703de94091cfdcdecf5a2c91bae4be
    Related-Bug: 1778098
    (cherry picked from commit acf7a29609c81529981b9e4a167c63faa78819d8)