OPENDJ-842 (CR-1699) On Windows, the setup command hangs when the length of the install path is too long


In order to avoid getting errors like "The input line is too long" on windows, a common way to fix this is to provide a "bootstrap" empty jar which contains only a MANIFEST.MF file listing all the application's jars in the "Class-Path" attribute.
This URL describes well enough the problem: http://ant.apache.org/manual/Tasks/manifestclasspath.html


build.xml:
In "prepackage" target, build bootstrap.jar.

_script-util.bat, _script-util.sh:
Replaced appending all the jars under libs with just the bootstrap jar.

Utilities.java, Utils.java, UpgradeUtils.java:
In getInstallPathFromClasspath(), extracted getInstallPath() and simplified its code a lot.

Installation.java, Installation.java:
Changed OPEN_DS_JAR_RELATIVE_PATHS into OPEN_DJ_BOOTSTRAP_JAR_RELATIVE_PATH.