Please improve the doc '2.6.1. Deploying the APIManager custom resource'

Please provide more details in the documentation at
https://access.redhat.com/documentation/en-us/red_hat_3scale_api_management/2.8/html-single/installing_3scale/index#deploying-apimanager-custom-resource
in the section 2'.6.1. Deploying the APIManager custom resource'.

In step 1:

• In OCP 4 there is different path, namely Operators > Installed Operators instead of Catalog > Installed Operators
• I suggest to use the new operator name 'Red Hat Integration - 3scale'

In step 4:

• I would like to improve the description of wildcardDomain. The actual description is pretty vague and I still do not know what I should fill there