Preferences: Timeout preferences should not set system properties but operation specific timeout

In JBIDE-16046 we introduced an Eclipse Preferences to set the openshift-java-clilent timeouts. These preferences currently set the lib specific system property which is not good. Consider the following usecase:

1) User launches Eclipse and has system property set to 10000 (-D): Eclipse Preferences display 10000
2) User sets preference to 1234
3) restarts Ecllipse: Preferences display 1234

3) happens because we load the value from eclipse preferences and override the system property
We should keep both separate: System property and Eclipse preferences:

We use operation specific timeouts in all Eclipse code and make the Eclipse preferences provide some value for this. Leaving the system property alone.

We should also:

• add a checkbox for "[ ] use default"
• change openshift-java-client to differentiate "no value" (<0) and value set (>=0)
• remove current hard-coded safe default in openshift-java-client, replace it by system-property we already have).