Updates to technical accuracy and completeness for section "Externalize HTTP Sessions to Red Hat Data Grid" in the Configuration Guide for EAP 7.3 beta.

https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.3.beta/html-single/configuration_guide/index#jdg_externalize_http_sessions

Feedback from amanukya@redhat.com:

• CLI commands only in docs is not helpful. Not everyone uses the EAP. Should provide more XML examples that result from CLI steps.
• Cannot find the `hotrod-session-management` configuration procedure.

1. create remote-cache-container in infinispan subsystem:

```
<remote-cache-container name="web-sessions" default-remote-cluster="rhdg-server-cluster" module="org.wildfly.clustering.web.hotrod">
<remote-clusters>
<remote-cluster name="rhdg-server-cluster" socket-bindings="remote-jdg-server1"/>
</remote-clusters>
</remote-cache-container>
```

2. Create the following cache configuration in infinispan subsystem `web` cache-container:

```
<invalidation-cache name="sessionCache">
<hotrod-store remote-cache-container="web-sessions" fetch-state="false" purge="false" passivation="false" shared="true" />
<locking isolation="REPEATABLE_READ"/>
</invalidation-cache>
```

3. Set in `socket-binding-group` the following:

```
<outbound-socket-binding name="remote-jdg-server1">
<remote-destination host="127.0.0.1" port="11222"/>
</outbound-socket-binding>
```

4. Set in distributable-web subsystem the following:

```
<hotrod-session-management name="default" remote-cache-container="web-sessions" cache-configuration="default" granularity="SESSION||ATTRIBUTE">
<local-affinity/>
</hotrod-session-management>
```