Allow ability to set security context for postgres deployment (#1517)

- Added docs for securityContext 
- enabled web securityContext configuration

Co-authored-by: Christian M. Adams <chadams@redhat.com>

config/crd/bases/awx.ansible.com_awxs.yaml

@@ -1779,6 +1779,10 @@ spec:
               session_cookie_secure:
                 description: Set session cookie secure mode for web
                 type: string
+              postgres_security_context_settings:
+                description: Key/values that will be set under the pod-level securityContext field
+                type: object
+                x-kubernetes-preserve-unknown-fields: true
               receptor_log_level:
                 description: Set log level of receptor service
                 type: string

config/manifests/bases/awx-operator.clusterserviceversion.yaml

@@ -61,6 +61,11 @@ spec:
         x-descriptors:
         - urn:alm:descriptor:com.tectonic.ui:advanced
         - urn:alm:descriptor:com.tectonic.ui:hidden
+      - displayName: PostgreSQL Security Context Settings
+        path: postgres_security_context_settings
+        x-descriptors:
+        - urn:alm:descriptor:com.tectonic.ui:advanced
+        - urn:alm:descriptor:com.tectonic.ui:hidden      
       - displayName: PostgreSQL Image
         path: postgres_image
         x-descriptors: