Design docs ironic diagram (#537)

* docs: Update Ironic diagram and restructure design docs

* fix: Update .gitignore to ignore macOS DS_Store files including in subdirs.  Remove existing DS_Store files lurking in tree

* docs: Fix trailing whitespaces....again

Author: OpenStackKen

Diff for: .gitignore

@@ -112,6 +112,9 @@ roles/**/molecule/**/__pycache__/
 
 # macOS
 .DS_Store
+._.DS_Store
+**/.DS_Store
+**/._.DS_Store
 
 # Temp location used by our scripts
 scripts/tmp/

Diff for: docs/assets/images/ironic-architecture.png

@@ -14,7 +14,7 @@ After switch and firewall configuration, deployment nodes are created with in th
 
 ### Ironic Diagram
 
-![conceptual_architecture](./assets/images/ironic-design.png)
+![conceptual_architecture](./assets/images/ironic-architecture.png)
 
 #### Benefits of Ironic
 

Diff for: docs/assets/images/ironic-design.png

@@ -137,7 +137,8 @@ nav:
       - Regions in OpenStack: openstack-cloud-design-regions.md
       - Availability Zones in OpenStack: openstack-cloud-design-az.md
       - Host Aggregates in OpenStack: openstack-cloud-design-ha.md
-      - Infrastructre Design: infrastructure-design.md
+      - Other Design Documentation:
+          - Genestack Infrastructure Design: openstack-cloud-design-genestack-infra.md
   - Deployment Guide:
       - What is Genestack?: deployment-guide-welcome.md
       - Getting Started: