Fix errors in downstream Getting Started guide

As reported by mmedek@redhat.com, several corrections are required in the latest build of the downstream Debezium Getting Started Guide:

• In Step 1 of Deploying a MySQL database (proc-deploying-mysql-database.adoc) the oc new-app step should include the label app=mysql, as is used later in the document, for example:

 

oc new-app -l app=mysql --name=mysql quay.io/debezium/example-mysql:latest

* In Step, 2, mysql is a deployment object, not a deployment config. So the example should be updated to match the following:

 

 

oc set env deployment/mysql MYSQL_ROOT_PASSWORD=debezium MYSQL_USER=mysqluser MYSQL_PASSWORD=mysqlpw

* In in Example 2.1 in proc-deploying-kafka-connect.adoc, update the Kafka version in the kafkaConnect descriptor to 3.3.1, by replacing the hard-coded value for the version property with the {debezium-kafka-version} attribute

 

• A required configuration for kafkaConnect was omitted. See the descriptor in the attached file getting-started-kc.yml

       The example represents an excerpt from a KC descriptor. I've made that explicit in the sentence that introduces the example.

• As per the example in the attached file, specify the number of replicas, so that only 1 kafkaConnect pod is created
• Because the GS example is based on the MySQL connector, the connector descriptor should include the table.include.list property. Set its value to inventory.* or similar.
• In 2.3.2 and 2.3.3
  Replace the topic prefix inventory_connector with dbserver1
  Assigning a unified topic prefix simplifies the example and makes it more clear.

• 3.3 the tombstone message is null instead of the expected
  

Verify with ccranfor@redhat.com  whether action is required.

• 3.4.1 and 3.4.3 Replace instances of DeploymentConfig with Deployment and update the oc edit command from oc edit dc/my-connect-cluster-connect to the following:
  oc edit deployment/my-connect-cluster-connect