Pagination support for server list API

[OpenStack Infra]

https://review.openstack.org/514506
Dear bug triager. This bug was created since a commit was marked with DOCIMPACT.
Your project "openstack/mogan" is set up so that we directly report the documentation bugs against it. If this needs changing, the docimpact-group option needs to be added for the project. You can ask the OpenStack infra team (#openstack-infra on freenode) for help if you need to.

commit 05cc14d39997cf13f43298852824fbca3c6a3ddf
Author: Xinran <email address hidden>
Date: Tue Oct 24 10:13:48 2017 +0800

    Pagination support for server list API

    We should support to return a list of servers according to users' requirements.
    In this patch, marker, limit, sort_key and sort_dir were added in server list
    API.
    - marker is used to display a list of servers after marker
    - limit is used to determinate the maximum number of servers to display
    - sort_key is used to sort the returned server list by specified key value
    - sort_dir is used to select a sort direction

    DocImpact
    APIImpact

    Change-Id: Id70e965794c82a0a29e53d4364f65b0f39042c7c
    Closes-Bug: #1726665