Server Adapter: allow user to customize the startup timeout to adapt to different server (speeds)

Whe you start the OpenShift server adapter it'll wait for the build to finish and the pod to appear. The timeout for this is not customisable, currently. This leads to things working fine in a (fast) local CDK while it timeouts on slower remote OpenShift server instances (like https://open.paas.redhat.com). See https://issues.jboss.org/browse/JBIDE-25916?focusedCommentId=13591082&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13591082
We should allow the users to customize and persist the initial timeout that the adapter waits for a pod to appear.