Kuryr: Add not on Service.spec.sessionAffinity

The aforementioned option is not supported by Kuryr (due to OVN Octavia
limitations), so this commit explicitly lists it on "Known limitations
of installing with Kuryr" page.

Author: dulek

modules/installation-osp-kuryr-known-limitations.adoc

@@ -19,6 +19,8 @@ Using {product-title} with Kuryr SDN has several limitations that apply to all v
 
 * If the subnet on which machines are created is not connected to a router, or if the subnet is connected, but the router has no external gateway set, Kuryr cannot create floating IPs for `Service` objects with type `LoadBalancer`.
 
+* Configuring the `sessionAffinity=ClientIP` property on `Service` objects does not have an effect. Kuryr does not support this setting.
+
 [discrete]
 [id="openstack-version-limitations_{context}"]
 == {rh-openstack} version limitations