Move reseller spec for Liberty release

We already have implemented the following features:

- A new field will be added to the project table to represent if that
  project has the domain feature;
- Update the domain operations to execute in the project table
- Allow create subdomain using a parent_id
- Migrate the domains for project table
- Drop domain table

Now in liberty release we want work to approve this features.

The other features mentioned in this spec will not be implemeted since
we need to discuss better in the next summit, there is:

- Migrate the role assignments for DomainUser and DomainGroups types.
- Provide dual scoped token for a project with domain feature

previously-approved: kilo

Change-Id: If357f38a8d81b094f47cd1a055dbec7edfb945ae
Implements: bp reseller

doc/source/index.rst

@@ -44,6 +44,14 @@ Kilo approved specs:
 
    specs/kilo/*
 
+Liberty approved specs:
+
+.. toctree::
+   :glob:
+   :maxdepth: 1
+
+   specs/liberty/*
+
 Keystone client approved specs:
 
 .. toctree::