[EAP7] Support clean shutdown on TERM

Feature: Replaced the EAP7 image prestop hooks in application templates with a TERM signal handler in the EAP7 openshift-launch script. Reason: Relying on a prestop hook for clean shutdown of EAP7 on a TERM signal adds an extra 2 seconds to termination. A TERM handler in the openshift-launch scripts cleanly terminates the EAP7 images without the 2 second delay. Result : The openshift-launch script wrapper now sets a trap for a TERM signal, forks the EAP7 application process in the background, then waits for EAP process to terminate. When a TERM signal is given, the wrapper process catches the signal and runs the jboss-cli script to cleanly shutdown the EAP process.