Add possibility specifying affinity of AWX Pods. (#1139)

* Add an option to specify affinity rules for the awx pod

In some cases, you may want to use affinity rules instead of a
 node selector so you can have more flexbility. For example if you want
to have "soft" rules i.e. run my pod on this node if possible otherwise
run it anywhere

* Rename `node_affinity` to `affinity`
* Maintain defaults and CSV
* Add fields validation

Co-authored-by: Olivier <oliverf1ca@yahoo.com>

roles/installer/defaults/main.yml

@@ -81,6 +81,8 @@ node_selector: ''
 #         app.kubernetes.io/name: "<resourcename>"
 topology_spread_constraints: ''
 
+affinity: {}
+
 # Add node tolerations for the AWX pods. Specify as literal block. E.g.:
 # tolerations: |
 #   - key: "dedicated"

roles/installer/templates/deployments/deployment.yaml.j2

@@ -379,6 +379,10 @@ spec:
       topologySpreadConstraints:
         {{ topology_spread_constraints | indent(width=8) }}
 {% endif %}
+{% if affinity | length %}
+      affinity:
+        {{ affinity | to_nice_yaml | indent(width=8) }}
+{% endif %}
 {% if tolerations %}
       tolerations:
         {{ tolerations | indent(width=8) }}