Documentation, 7.4.0.Beta template change instructions

Not sure if this is already tracked somewhere. But in 7.4.0.Beta templates location [1] and folder structure has changed and that means that requires changes in documentation as well.

So from quick look (this is not ultimate list) at least this needs to be changed:

• Chapter 2.4. Import the Latest JBoss EAP for OpenShift Imagestreams and Templates
• all occurences where in 73 documentation eap73-openjdk11-* is mentioned are candidate for change

This Jira also covers the SME feedback provided in JBEAP-20980.[3]

[1] https://github.com/jboss-container-images/jboss-eap-openshift-templates/tree/eap74-beta-dev
[2] https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.3/html-single/getting_started_with_jboss_eap_for_openshift_container_platform/index#import_imagestreams_templates

[3] https://issues.redhat.com/browse/JBEAP-20980?focusedCommentId=15823276&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15823276