Adjust Kie server system properties descriptions

Kie Server system properties descriptions are not aligned with the ones used in the documentation [1][2].

We also want to unify the Kie Server term to replace the Process Server and Decision Server [BXMSPROD-505]. For that we have to update some property descriptions as the following ones in [1]:

• org.kie.dmn.server.ext.disabled: If set to true, disables the Process Server DMN support.
• org.kie.swagger.server.ext.disabled: If set to true, disables the Process Server swagger documentation support

And likewise in [2]:

• org.kie.dmn.server.ext.disabled: If set to true, disables the Decision Server DMN support.
• org.kie.swagger.server.ext.disabled: If set to true, disables the Decision Server swagger documentation support

[1] https://access.redhat.com/documentation/en-us/red_hat_process_automation_manager/7.5/html-single/managing_and_monitoring_process_server/index#kie-server-system-properties-ref_execution-server
[2] https://access.redhat.com/documentation/en-us/red_hat_decision_manager/7.5/html-single/managing_and_monitoring_decision_server/index#kie-server-system-properties-ref_execution-server