Document vendor support information

In the future, I'd like for this doc to be generated from the vendors.py
file, but for now, this is great.

Change-Id: Ifd0c8da5da46ba156c789f05398abcfa689f4f01

doc/source/index.rst

@@ -3,6 +3,7 @@
 .. toctree::
    :maxdepth: 2
 
+   vendor-support
    contributing
    installation
 

doc/source/vendor-support.rst

@@ -0,0 +1,86 @@
+==============
+Vendor Support
+==============
+
+OpenStack presents deployers with many options, some of which can expose
+differences to end users. `os-client-config` tries its best to collect
+information about various things a user would need to know. The following
+is a text representation of the vendor related defaults `os-client-config`
+knows about.
+
+HP Cloud
+--------
+
+https://region-b.geo-1.identity.hpcloudsvc.com:35357/v2.0
+
+============== ================
+Region Name    Human Name
+============== ================
+region-a.geo-1 US West
+region-b.geo-1 US East
+============== ================
+
+* DNS Service Type is `hpext:dns`
+* Image API Version is 1
+* Images must be in `qcow2` format
+
+Rackspace
+---------
+
+https://identity.api.rackspacecloud.com/v2.0/
+
+============== ================
+Region Name    Human Name
+============== ================
+DFW            Dallas
+ORD            Chicago
+IAD            Washington, D.C.
+============== ================
+
+* Database Service Type is `rax:database`
+* Compute Service Name is `cloudServersOpenStack`
+* Image API Version is 2
+* Images must be in `vhd` format
+
+Dreamhost
+---------
+
+https://keystone.dream.io/v2.0
+
+============== ================
+Region Name    Human Name
+============== ================
+RegionOne      Region One
+============== ================
+
+* Image API Version is 2
+* Images must be in `raw` format
+
+Vexxhost
+--------
+
+http://auth.api.thenebulacloud.com:5000/v2.0/
+
+============== ================
+Region Name    Human Name
+============== ================
+ca-ymq-1       Montreal
+============== ================
+
+* Image API Version is 1
+* Images must be in `qcow2` format
+
+RunAbove
+--------
+
+https://auth.runabove.io/v2.0
+
+============== ================
+Region Name    Human Name
+============== ================
+SBG-1          Strassbourg, FR
+BHS-1          Beauharnois, QC
+============== ================
+
+* Image API Version is 1
+* Images must be in `qcow2` format