doc: drop sphinxcontrib-nwdiag, sphinxcontrib-blockdiag usage

sphinxcontrib-nwdiag does not appear to be maintained anymore [1] and
there have been no releases in nearly 5 years. Statically generate the
images and include them this way. We can revert this change if the
maintainership issue resolves itself.

sphinxcontrib-blockdiag has had activity more recently [2], but it's
still been nearly 3 years. More importantly, we don't actually use it so
there's no reason to keep it around.

[1] https://pypi.org/project/sphinxcontrib-nwdiag/#history
[1] https://pypi.org/project/sphinxcontrib-blockdiag/#history

Change-Id: Ic5244c792acd01f8aec5ff626e53303c1738aa69
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

doc/requirements.txt

@@ -4,8 +4,4 @@ Pygments
 docutils
 sphinx>=2.0.0,!=2.1.0 # BSD
 openstackdocstheme>=2.2.1 # Apache-2.0
-nwdiag
-blockdiag
-sphinxcontrib-blockdiag
-sphinxcontrib-nwdiag
 zuul-sphinx>=0.2.0

doc/source/conf.py

@@ -23,14 +23,14 @@
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = [ 'sphinx.ext.autodoc',
-               'zuul_sphinx',
-               'openstackdocstheme',
-               'sphinxcontrib.blockdiag',
-               'sphinxcontrib.nwdiag' ]
+extensions = [
+    'sphinx.ext.autodoc',
+    'zuul_sphinx',
+    'openstackdocstheme',
+]
 
 # openstackdocstheme options
-openstackdocs_repo_name = 'openstack-dev/devstack'
+openstackdocs_repo_name = 'openstack/devstack'
 openstackdocs_pdf_link = True
 openstackdocs_bug_project = 'devstack'
 openstackdocs_bug_tag = ''

doc/source/guides/neutron.rst

@@ -41,19 +41,8 @@ network and is on a shared subnet with other machines.  The
 `local.conf` exhibited here assumes that 1500 is a reasonable MTU to
 use on that network.
 
-.. nwdiag::
-
-        nwdiag {
-                inet [ shape = cloud ];
-                router;
-                inet -- router;
-
-                network hardware_network {
-                        address = "172.18.161.0/24"
-                        router [ address = "172.18.161.1" ];
-                        devstack-1 [ address = "172.18.161.6" ];
-                }
-        }
+.. image:: /assets/images/neutron-network-1.png
+   :alt: Network configuration for a single DevStack node
 
 
 DevStack Configuration
@@ -100,21 +89,8 @@ also want to do multinode testing and networking.
 Physical Network Setup
 ~~~~~~~~~~~~~~~~~~~~~~
 
-.. nwdiag::
-
-        nwdiag {
-                inet [ shape = cloud ];
-                router;
-                inet -- router;
-
-                network hardware_network {
-                        address = "172.18.161.0/24"
-                        router [ address = "172.18.161.1" ];
-                        devstack-1 [ address = "172.18.161.6" ];
-                        devstack-2 [ address = "172.18.161.7" ];
-                }
-        }
-
+.. image:: /assets/images/neutron-network-2.png
+   :alt: Network configuration for multiple DevStack nodes
 
 After DevStack installs and configures Neutron, traffic from guest VMs
 flows out of `devstack-2` (the compute node) and is encapsulated in a
@@ -222,8 +198,6 @@ connect OpenStack nodes (like `devstack-2`) together. This bridge is
 used so that project network traffic, using the VXLAN tunneling
 protocol, flows between each compute node where project instances run.
 
-
-
 DevStack Compute Configuration
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -268,30 +242,8 @@ to the neutron L3 service.
 Physical Network Setup
 ----------------------
 
-.. nwdiag::
-
-        nwdiag {
-                inet [ shape = cloud ];
-                router;
-                inet -- router;
-
-                network provider_net {
-                        address = "203.0.113.0/24"
-                        router [ address = "203.0.113.1" ];
-                        controller;
-                        compute1;
-                        compute2;
-                }
-
-                network control_plane {
-                        router [ address = "10.0.0.1" ]
-                        address = "10.0.0.0/24"
-                        controller [ address = "10.0.0.2" ]
-                        compute1 [ address = "10.0.0.3" ]
-                        compute2 [ address = "10.0.0.4" ]
-                }
-        }
-
+.. image:: /assets/images/neutron-network-3.png
+   :alt: Network configuration for provider networks
 
 On a compute node, the first interface, eth0 is used for the OpenStack
 management (API, message bus, etc) as well as for ssh for an