Check if keycloak app is already deployed and available before invoking kcadm.sh

[arso]

In current implementation there is an ugly sleep(30) used to makes sure the setup code is not trying to run kcadm.sh before keycloak rest api is up and running.
In order to get rig of this hardcode we can think of a better solution ie. search for some 'healthcheck' type of endpoint we could ping in short intervals ... or if that's not the case implement proper (and simple) re-try mechanism.