Convert API Reference to RST and host it in the Nova tree (Ocata)

Gerrit topic: https://review.openstack.org/#q,topic:bp/api-ref-in-rst-ocata,n,z

Addressed by: https://review.openstack.org/371458
    Add description for v2.20 changes in api-ref

Addressed by: https://review.openstack.org/371481
    Add description for 2.9 microversion

Addressed by: https://review.openstack.org/371496
    Add reserved param for v2.4

Gerrit topic: https://review.openstack.org/#q,topic:bp/api-ref-in-rst,n,z

Addressed by: https://review.openstack.org/338051
    api-ref: Complete all the verifications of remote consoles

Addressed by: https://review.openstack.org/372203
    Add link ref to nova api concept doc

Addressed by: https://review.openstack.org/338606
    Complete verification of servers-action-fixed-ip.inc

Addressed by: https://review.openstack.org/329704
    Complete verification for os-floating-ips

Addressed by: https://review.openstack.org/374061
    Add more description when service delete

Addressed by: https://review.openstack.org/383683
    api-ref: Body verification for os-simple-tenant-usage.inc

Addressed by: https://review.openstack.org/383691
    pi-ref: Body verification for os-hypervisors.inc

Addressed by: https://review.openstack.org/384664
    API Ref: update server_id params

Gerrit topic: https://review.openstack.org/#q,topic:bug/1641713,n,z

Addressed by: https://review.openstack.org/397378
    api-ref: method verification for server-migrations

Addressed by: https://review.openstack.org/397382
    api-ref: parameter verification for server-migrations

Addressed by: https://review.openstack.org/397386
    api-ref: example verification for server-migrations

Addressed by: https://review.openstack.org/397400
    api-ref: body verification for list server migrations

Addressed by: https://review.openstack.org/397402
    api-ref: body verification for show server migration

Addressed by: https://review.openstack.org/397406
    api-ref: body verification for force_complete server migration

Addressed by: https://review.openstack.org/397407
    api-ref: body verification for abort live migration

Addressed by: https://review.openstack.org/398197
    api-ref: body verification for os-hypervisors

Addressed by: https://review.openstack.org/398233
    api-ref: verification for os-server-actions(1)

Addressed by: https://review.openstack.org/410191
    make 2.31 micorversion wording better

Addressed by: https://review.openstack.org/410193
    Better wording for micorversion 2.36

Addressed by: https://review.openstack.org/413658
    correct misleading wording

I'm marking this complete for Ocata. I've created a blueprint for Pike to continue the work there:

https://blueprints.launchpad.net/nova/+spec/api-ref-in-rst-pike

Please move any remaining patches targeted to this blueprint to that blueprint.

-- mriedem 20170203

Addressed by: https://review.openstack.org/458738
    Move all the deprecated server actions together into the bottom of doc

Addressed by: https://review.openstack.org/461998
    Adjust the order of server actions in api-ref